Make your practice count.Sign in to track completed questions across devices. Everything is free to browse.
Rohit Negi · Coder Army
Rohit Negi DSA Sheet
Beginner-to-advanced practice across data structures and algorithms.
726 practice entries · Source checked
0 / 726 completed0%
About this source edition
Creator-published spreadsheet
“Source checked” is when this edition was retrieved, not a claim that the creator updated it then.
Original sheet ↗Array
0 / 45
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Search an Element in an array | Easy | Open ↗ | — | |
| Check if two arrays are equal or not | Easy | Open ↗ | — | |
| Missing element of AP | Easy | Open ↗ | — | |
| Cyclically rotate an array by one | Easy | Open ↗ | — | |
| Find minimum and maximum element in an array | Easy | Open ↗ | — | |
| Binary Array Sorting | Easy | Open ↗ | — | |
| Move all negative elements to end | Easy | Open ↗ | — | |
| Missing number | Easy | Open ↗ | — | |
| Search Element in Matrix | Easy | Open ↗ | — | |
| Find the fine | Easy | Open ↗ | — | |
| Greater on right side | Easy | Open ↗ | — | |
| Remove duplicate elements from sorted Array | Easy | Open ↗ | — | |
| Subarray with given sum | Easy | Open ↗ | — | |
| Sort an array of 0s, 1s and 2s | Easy | Open ↗ | — | |
| Equilibrium Point | Easy | Open ↗ | — | |
| Peak element | Easy | Open ↗ | — | |
| Find Transition Point | Easy | Open ↗ | — | |
| Alternate positive and negative numbers | Easy | Open ↗ | — | |
| Union of Two Sorted Arrays | Easy | Open ↗ | — | |
| Three way partitioning | Easy | Open ↗ | — | |
| Frogs and Jumps | Easy | Open ↗ | — | |
| Min Subsets with Consecutive Numbers | Easy | Open ↗ | — | |
| Find Missing And Repeating | Medium | Open ↗ | — | |
| Rearrange Array Alternately | Medium | Open ↗ | — | |
| Pythagorean Triplet | Medium | Open ↗ | — | |
| Rearrange an array with O(1) extra space | Medium | Open ↗ | — | |
| Count triplets with sum smaller than X | Medium | Open ↗ | — | |
| Boolean Matrix | Medium | Open ↗ | — | |
| Row with max 1s | Medium | Open ↗ | — | |
| Container With Most Water | Medium | Open ↗ | — | |
| Maximum Triplet product | Medium | Open ↗ | — | |
| Coins of Geekland | Medium | Open ↗ | — | |
| Next Permutation | Medium | Open ↗ | — | |
| Rotate Image | Medium | Open ↗ | — | |
| Count Primes | Medium | Open ↗ | — | |
| Watering Plants | Medium | Open ↗ | — | |
| Arithmetic Subarrays | Medium | Open ↗ | — | |
| Majority Element | Medium | Open ↗ | — | |
| Max Circular Subarray Sum | Hard | Open ↗ | — | |
| Count the subarrays having product less than k | Hard | Open ↗ | — | |
| Maximum subset XOR | Hard | Open ↗ | — | |
| Next Smallest Palindrome | Hard | Open ↗ | — | |
| Count the number of subarrays | Hard | Open ↗ | — | |
| Largest rectangle of 1s with swapping of columns allowed | Hard | Open ↗ | — | |
| N/3 Repeat Number | Hard | Open ↗ | — |
String
0 / 39
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Reverse a String | Easy | Open ↗ | — | |
| Check if strings are rotations of each other or not | Easy | Open ↗ | — | |
| Maximum Occuring Character | Easy | Open ↗ | — | |
| Binary String | Easy | Open ↗ | — | |
| Anagram of String | Easy | Open ↗ | — | |
| Merge two strings | Easy | Open ↗ | — | |
| Reverse words in a given string | Easy | Open ↗ | — | |
| Palindrome String | Easy | Open ↗ | — | |
| Longest Common Prefix in an Array | Easy | Open ↗ | — | |
| Roman Number to Integer | Easy | Open ↗ | — | |
| Length of Last Word | Easy | Open ↗ | — | |
| Longest Distinct characters in string | Easy | Open ↗ | — | |
| Remove all duplicates from a given string | Easy | Open ↗ | — | |
| Min Number of Flips | Easy | Open ↗ | — | |
| Meta Strings | Easy | Open ↗ | — | |
| Smallest window containing 0, 1 and 2 | Easy | Open ↗ | — | |
| Generate Grey Code Sequences | Easy | Open ↗ | — | |
| Sum of two large numbers | Medium | Open ↗ | — | |
| Length of the longest substring | Medium | Open ↗ | — | |
| Longest Prefix Suffix | Medium | Open ↗ | — | |
| Smallest distinct window | Medium | Open ↗ | — | |
| Case-specific Sorting of Strings | Medium | Open ↗ | — | |
| Excel Sheet | Part - 1 | Medium | Open ↗ | — | |
| Transform String | Medium | Open ↗ | — | |
| Remove and Reverse | Medium | Open ↗ | — | |
| String formation from substring | Medium | Open ↗ | — | |
| Minimum Days | Medium | Open ↗ | — | |
| Remove Consecutive Characters | Medium | Open ↗ | — | |
| Bulls and Cows | Medium | Open ↗ | — | |
| Atoi | Medium | Open ↗ | — | |
| Valid Ip Addresses | Hard | Open ↗ | — | |
| Integer To Roman | Hard | Open ↗ | — | |
| Minimum characters to be added at front to make string palindrome | Hard | Open ↗ | — | |
| Wildcard string matching | Hard | Open ↗ | — | |
| Longest Palindromic Substring in Linear Time | Hard | Open ↗ | — | |
| Numbers with one absolute difference | Hard | Open ↗ | — | |
| Stringoholics | Hard | Open ↗ | — | |
| Power of 2 | Hard | Open ↗ | — | |
| Justified Text | Hard | Open ↗ | — |
Searching and Sorting
0 / 65
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Searching an element in a sorted array | Easy | Open ↗ | — | |
| Last index of One | Easy | Open ↗ | — | |
| Count the Zeros | Easy | Open ↗ | — | |
| Elements in the Range | Easy | Open ↗ | — | |
| Bubble Sort | Easy | Open ↗ | — | |
| Insertion Sort | Easy | Open ↗ | — | |
| First and last occurrences of X | Easy | Open ↗ | — | |
| Count zeros in a sorted matrix | Easy | Open ↗ | — | |
| Array Subset of another array | Easy | Open ↗ | — | |
| Selection Sort | Easy | Open ↗ | — | |
| Floor in a Sorted Array | Easy | Open ↗ | — | |
| Radix Sort | Easy | Open ↗ | — | |
| Search in a matrix | Easy | Open ↗ | — | |
| Bitonic Point | Easy | Open ↗ | — | |
| Two Repeated Elements | Easy | Open ↗ | — | |
| Count More than n/k Occurences | Easy | Open ↗ | — | |
| Number and the Digit Sum | Easy | Open ↗ | — | |
| Find triplets with zero sum | Easy | Open ↗ | — | |
| Sort The Array | Easy | Open ↗ | — | |
| Sort in specific order | Easy | Open ↗ | — | |
| Sort a String | Easy | Open ↗ | — | |
| Triplet Family | Easy | Open ↗ | — | |
| Merge and Sort | Easy | Open ↗ | — | |
| Merging two unsorted arrays in sorted order | Easy | Open ↗ | — | |
| Rope Cutting | Easy | Open ↗ | — | |
| Make array elements unique | Easy | Open ↗ | — | |
| Kth smallest element | Medium | Open ↗ | — | |
| Smallest Positive missing number | Medium | Open ↗ | — | |
| Sort an array according to the other | Medium | Open ↗ | — | |
| Square root of a number | Medium | Open ↗ | — | |
| Search in a row-column sorted Matrix | Medium | Open ↗ | — | |
| Smallest factorial number | Medium | Open ↗ | — | |
| Merge Sort | Medium | Open ↗ | — | |
| Quick Sort | Medium | Open ↗ | — | |
| Count Inversions | Medium | Open ↗ | — | |
| Find All Four Sum Numbers | Medium | Open ↗ | — | |
| Minimum Swaps to Sort | Medium | Open ↗ | — | |
| Number of pairs | Medium | Open ↗ | — | |
| Sort an Array | Medium | Open ↗ | — | |
| Sorting Elements of an Array by Frequency | Medium | Open ↗ | — | |
| Overlapping Intervals | Medium | Open ↗ | — | |
| Find minimum number of Laptops required | Medium | Open ↗ | — | |
| LCP | Medium | Open ↗ | — | |
| Reach a Number | Medium | Open ↗ | — | |
| Heaters | Medium | Open ↗ | — | |
| Friends Of Appropriate Ages | Medium | Open ↗ | — | |
| Koko Eating Bananas | Medium | Open ↗ | — | |
| 3Sum | Medium | Open ↗ | — | |
| 3Sum Closest | Medium | Open ↗ | — | |
| Nth Digit | Medium | Open ↗ | — | |
| Sort a 2D vector diagonally | Medium | Open ↗ | — | |
| Maximum Intersecting Lines | Medium | Open ↗ | — | |
| Merge Without Extra Space | Hard | Open ↗ | — | |
| Median of the Subarrays | Hard | Open ↗ | — | |
| Median of Array | Hard | Open ↗ | — | |
| Implement Power Function | Hard | Open ↗ | — | |
| WoodCutting Made Easy! | Hard | Open ↗ | — | |
| Matrix Median | Hard | Open ↗ | — | |
| Allocate Books | Hard | Open ↗ | — | |
| Painter's Partition Problem | Hard | Open ↗ | — | |
| Red Zone | Hard | Open ↗ | — | |
| Max Sum of Rectangle No Larger Than K | Hard | Open ↗ | — | |
| Smallest Good Base | Hard | Open ↗ | — | |
| House Robber IV | Hard | Open ↗ | — | |
| Maximum Gap | Hard | Open ↗ | — |
LinkedList
0 / 59
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Print Linked List elements | Easy | Open ↗ | — | |
| Linked List Insertion | Easy | Open ↗ | — | |
| Count nodes of linked list | Easy | Open ↗ | — | |
| Check If Circular Linked List | Easy | Open ↗ | — | |
| Identical Linked Lists | Easy | Open ↗ | — | |
| Insert in a Sorted List | Easy | Open ↗ | — | |
| Insert in Middle of Linked List | Easy | Open ↗ | — | |
| Delete node in Doubly Linked List | Easy | Open ↗ | — | |
| Reverse a Doubly Linked List | Easy | Open ↗ | — | |
| Delete Alternate Nodes | Easy | Open ↗ | — | |
| Find the Sum of Last N nodes of the Linked List | Easy | Open ↗ | — | |
| Find n/k th node in Linked list | Easy | Open ↗ | — | |
| Detect Loop in linked list | Easy | Open ↗ | — | |
| Move Last Element to Front of a Linked List | Easy | Open ↗ | — | |
| Nth node from end of linked list | Easy | Open ↗ | — | |
| Finding middle element in a linked list | Easy | Open ↗ | — | |
| Reverse a linked list | Easy | Open ↗ | — | |
| Remove duplicate element from sorted Linked List | Easy | Open ↗ | — | |
| Delete without head pointer | Easy | Open ↗ | — | |
| Remove duplicates from an unsorted linked list | Easy | Open ↗ | — | |
| Delete a Node in Single Linked List | Easy | Open ↗ | — | |
| Given a linked list of 0s, 1s and 2s, sort it. | Easy | Open ↗ | — | |
| Find length of Loop | Easy | Open ↗ | — | |
| Intersection of two sorted Linked lists | Easy | Open ↗ | — | |
| Pairwise swap elements of a linked list | Easy | Open ↗ | — | |
| Sorted insert for circular linked list | Easy | Open ↗ | — | |
| Count Pairs whose sum is equal to X | Easy | Open ↗ | — | |
| Intersection of Two Linked Lists | Easy | Open ↗ | — | |
| Split a Circular Linked List into two halves | Easy | Open ↗ | — | |
| Union of Two Linked Lists | Easy | Open ↗ | — | |
| Linked List Matrix | Easy | Open ↗ | — | |
| XOR Linked List | Easy | Open ↗ | — | |
| Remove loop in Linked List | Medium | Open ↗ | — | |
| Intersection Point in Y Shaped Linked Lists | Medium | Open ↗ | — | |
| Check if Linked List is Palindrome | Medium | Open ↗ | — | |
| Rotate a Linked List | Medium | Open ↗ | — | |
| Merge two sorted linked lists | Medium | Open ↗ | — | |
| Delete nodes having greater value on right | Medium | Open ↗ | — | |
| Merge Sort for Linked List | Medium | Open ↗ | — | |
| Rearrange a linked list | Medium | Open ↗ | — | |
| Prime List | Medium | Open ↗ | — | |
| Length of longest palindrome in linked list | Medium | Open ↗ | — | |
| Reverse alternate nodes in Link List | Medium | Open ↗ | — | |
| Merge Sort on Doubly Linked List | Medium | Open ↗ | — | |
| Quick Sort on Linked List | Medium | Open ↗ | — | |
| QuickSort on Doubly Linked List | Medium | Open ↗ | — | |
| Remove all occurences of duplicates in a linked list | Medium | Open ↗ | — | |
| Insertion Sort for Singly Linked List | Medium | Open ↗ | — | |
| Reverse Alternate K Nodes | Medium | Open ↗ | — | |
| Linked List Cycle II | Medium | Open ↗ | — | |
| LRU Cache | Medium | Open ↗ | — | |
| Flatten a Multilevel Doubly Linked List | Medium | Open ↗ | — | |
| Clone a linked list with next and random pointer | Hard | Open ↗ | — | |
| Reorder List | Hard | Open ↗ | — | |
| Reverse a sublist of a linked list | Hard | Open ↗ | — | |
| LFU Cache | Hard | Open ↗ | — | |
| Reverse Nodes in k-Group | Hard | Open ↗ | — | |
| Design Skiplist | Hard | Open ↗ | — | |
| Subtraction in Linked List | Hard | Open ↗ | — |
Stack
0 / 39
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Immediate Smaller Element | Easy | Open ↗ | — | |
| Implement stack using array | Easy | Open ↗ | — | |
| Implement Stack using Linked List | Easy | Open ↗ | — | |
| Pairwise Consecutive Elements | Easy | Open ↗ | — | |
| Parenthesis Checker | Easy | Open ↗ | — | |
| Sort a stack | Easy | Open ↗ | — | |
| Delete middle element of a stack | Easy | Open ↗ | — | |
| Maximum Difference | Easy | Open ↗ | — | |
| Print Bracket Number | Easy | Open ↗ | — | |
| Max sum in sub-arrays | Easy | Open ↗ | — | |
| String Manipulation | Easy | Open ↗ | — | |
| Make the array beautiful | Easy | Open ↗ | — | |
| Next Greater Element I | Easy | Open ↗ | — | |
| Baseball Game | Easy | Open ↗ | — | |
| Backspace String Compare | Easy | Open ↗ | — | |
| Next Greater Element | Medium | Open ↗ | — | |
| Get minimum element from stack | Medium | Open ↗ | — | |
| The Celebrity Problem | Medium | Open ↗ | — | |
| Smallest number on left | Medium | Open ↗ | — | |
| Asteroid Collision | Medium | Open ↗ | — | |
| Remove K Digits | Medium | Open ↗ | — | |
| Valid Expression | Medium | Open ↗ | — | |
| Find Maximum Equal sum of Three Stacks | Medium | Open ↗ | — | |
| MAXSPPROD | Medium | Open ↗ | — | |
| Decode String | Medium | Open ↗ | — | |
| Evaluate Expression | Medium | Open ↗ | — | |
| Redundant Braces | Medium | Open ↗ | — | |
| Next Greater Element II | Medium | Open ↗ | — | |
| Clumsy Factorial | Medium | Open ↗ | — | |
| Maximum Rectangular Area in a Histogram | Hard | Open ↗ | — | |
| Maximum of minimum for every window size | Hard | Open ↗ | — | |
| IPL 2021 - Final | Hard | Open ↗ | — | |
| IPL 2021 - Match Day 6 - Semi Final | Hard | Open ↗ | — | |
| Rain Water Trapped | Hard | Open ↗ | — | |
| Simplify Directory Path | Hard | Open ↗ | — | |
| Basic Calculator | Hard | Open ↗ | — | |
| Create Maximum Number | Hard | Open ↗ | — | |
| Tag Validator | Hard | Open ↗ | — | |
| Max Chunks To Make Sorted II | Hard | Open ↗ | — |
Queue
0 / 24
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Queue Push & Pop | Easy | Open ↗ | — | |
| Queue Reversal | Easy | Open ↗ | — | |
| Implement Queue using array | Easy | Open ↗ | — | |
| Implement Queue using Linked List | Easy | Open ↗ | — | |
| Generate Binary Numbers | Easy | Open ↗ | — | |
| Stack using two queues | Easy | Open ↗ | — | |
| Queue using two Stacks | Easy | Open ↗ | — | |
| Reverse First K elements of Queue | Easy | Open ↗ | — | |
| Deque Implementations | Easy | Open ↗ | — | |
| Next Right Node | Easy | Open ↗ | — | |
| First Unique Character in a Str | Easy | Open ↗ | — | |
| Number of Recent Calls | Easy | Open ↗ | — | |
| Time Needed to Buy Tickets | Easy | Open ↗ | — | |
| First non-repeating character in a stream | Medium | Open ↗ | — | |
| Circular tour | Medium | Open ↗ | — | |
| Count the Reversals | Medium | Open ↗ | — | |
| Stack Permutations | Medium | Open ↗ | — | |
| Operations on PriorityQueue | Medium | Open ↗ | — | |
| Design Circular Deque | Medium | Open ↗ | — | |
| First non-repeating character in a stream of characters | Medium | Open ↗ | — | |
| Sliding Window Maximum | Medium | Open ↗ | — | |
| Stamping The Sequence | Hard | Open ↗ | — | |
| Minimum Number of K Consecutive Bit Flips | Hard | Open ↗ | — | |
| Count Subarrays With Fixed Bounds | Hard | Open ↗ | — |
Tree
0 / 60
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Inorder Traversal | Easy | Open ↗ | — | |
| Preorder Traversal | Easy | Open ↗ | — | |
| Postorder Traversal | Easy | Open ↗ | — | |
| Count Leaves in Binary Tree | Easy | Open ↗ | — | |
| Size of Binary Tree | Easy | Open ↗ | — | |
| Sum of Binary Tree | Easy | Open ↗ | — | |
| Count Non-Leaf Nodes in Tree | Easy | Open ↗ | — | |
| Left View of Binary Tree | Easy | Open ↗ | — | |
| Right View of Binary Tree | Easy | Open ↗ | — | |
| Height of Binary Tree | Easy | Open ↗ | — | |
| Root to leaf paths sum | Easy | Open ↗ | — | |
| Check for Balanced Tree | Easy | Open ↗ | — | |
| Determine if Two Trees are Identical | Easy | Open ↗ | — | |
| Level order traversal | Easy | Open ↗ | — | |
| Level order traversal in spiral form | Easy | Open ↗ | — | |
| Mirror Tree | Easy | Open ↗ | — | |
| Print all nodes that don't have sibling | Easy | Open ↗ | — | |
| Maximum Depth Of Binary Tree | Easy | Open ↗ | — | |
| Shortest distance in infinite tree | Easy | Open ↗ | — | |
| Largest value in each level | Easy | Open ↗ | — | |
| Perfect Binary Tree | Easy | Open ↗ | — | |
| Nodes at Odd Levels | Easy | Open ↗ | — | |
| Remove Half Nodes | Easy | Open ↗ | — | |
| Find the maximum GCD of the siblings of a Binary Tree | Easy | Open ↗ | — | |
| Maximum Node Level | Easy | Open ↗ | — | |
| Deletion in a Binary Tree | Easy | Open ↗ | — | |
| Check if two Nodes are Cousins | Easy | Open ↗ | — | |
| Vertical Order traversal of Binary Tree | Medium | Open ↗ | — | |
| Diagonal Traversal | Medium | Open ↗ | — | |
| Flatten Binary Tree to Linked List | Medium | Open ↗ | — | |
| Merge two Binary Tree | Medium | Open ↗ | — | |
| Maximum Edge Removal | Medium | Open ↗ | — | |
| Populate Next Right Pointers Tree | Medium | Open ↗ | — | |
| Burn a Tree | Medium | Open ↗ | — | |
| Boundary Traversal of binary tree | Medium | Open ↗ | — | |
| Diameter of a Binary Tree | Medium | Open ↗ | — | |
| Sum Tree | Medium | Open ↗ | — | |
| Top View of Binary Tree | Medium | Open ↗ | — | |
| Bottom View of Binary Tree | Medium | Open ↗ | — | |
| Lowest Common Ancestor in a Binary Tree | Medium | Open ↗ | — | |
| Maximum difference between node and its ancestor | Medium | Open ↗ | — | |
| Serialize and Deserialize a Binary Tree | Medium | Open ↗ | — | |
| Maximum sum of Non-adjacent nodes | Medium | Open ↗ | — | |
| Foldable Binary Tree | Medium | Open ↗ | — | |
| Construct Binary Tree from Parent Array | Medium | Open ↗ | — | |
| Make Binary Tree From Linked List | Medium | Open ↗ | — | |
| Check Mirror in N-ary tree | Medium | Open ↗ | — | |
| Inorder Traversal (Iterative) | Medium | Open ↗ | — | |
| Postorder Traversal (Iterative) | Medium | Open ↗ | — | |
| Print Nodes having K leaves | Medium | Open ↗ | — | |
| Print Binary Tree levels in sorted order | Medium | Open ↗ | — | |
| Nodes at given distance in binary tree | Hard | Open ↗ | — | |
| Burning Tree | Hard | Open ↗ | — | |
| Check if all levels of two trees are anagrams or not | Hard | Open ↗ | — | |
| Binary Tree to DLL | Hard | Open ↗ | — | |
| Maximum Path Sum between 2 Special Nodes | Hard | Open ↗ | — | |
| Scrambled String | Hard | Open ↗ | — | |
| Check Tree Traversal | Hard | Open ↗ | — | |
| Corona Vaccine | Hard | Open ↗ | — | |
| Recover a Tree From Preorder | Hard | Open ↗ | — |
Binary Search Tree
0 / 44
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Search a node in BST | Easy | Open ↗ | — | |
| Minimum element in BST | Easy | Open ↗ | — | |
| Check for BST | Easy | Open ↗ | — | |
| Insert a node in a BST | Easy | Open ↗ | — | |
| Kth largest element in BST | Easy | Open ↗ | — | |
| Inorder Traversal and BST | Easy | Open ↗ | — | |
| Binary Tree to BST | Easy | Open ↗ | — | |
| Median of BST | Easy | Open ↗ | — | |
| Kth Smallest Element In Tree | Easy | Open ↗ | — | |
| BST Iterator | Easy | Open ↗ | — | |
| 2-Sum Binary Tree | Easy | Open ↗ | — | |
| Find Common Nodes in two BSTs | Easy | Open ↗ | — | |
| Array to BST | Easy | Open ↗ | — | |
| Inorder Successor in BST | Easy | Open ↗ | — | |
| Print BST elements in given range | Easy | Open ↗ | — | |
| Check whether BST contains Dead End | Easy | Open ↗ | — | |
| Brothers From Different Roots | Easy | Open ↗ | — | |
| Sum of k smallest elements in BST | Easy | Open ↗ | — | |
| Minimum Distance Between | Easy | Open ↗ | — | |
| Normal BST to Balanced BST | Easy | Open ↗ | — | |
| Construct BST from Postorder | Easy | Open ↗ | — | |
| Recover Binary Search Tree | Medium | Open ↗ | — | |
| Valid BST from Preorder | Medium | Open ↗ | — | |
| k-th smallest element in BST | Medium | Open ↗ | — | |
| Delete a node from BST | Medium | Open ↗ | — | |
| Largest BST | Medium | Open ↗ | — | |
| Predecessor and Successor | Medium | Open ↗ | — | |
| Preorder to PostOrder | Medium | Open ↗ | — | |
| Find the Closest Element in BST | Medium | Open ↗ | — | |
| Ceil in BST | Medium | Open ↗ | — | |
| Preorder Traversal and BST | Medium | Open ↗ | — | |
| Bheem Wants Ladoos | Medium | Open ↗ | — | |
| Minimum Absolute Difference In BST | Medium | Open ↗ | — | |
| Valentine Sum | Medium | Open ↗ | — | |
| Pairs violating BST property | Medium | Open ↗ | — | |
| Remove BST keys outside given range | Medium | Open ↗ | — | |
| Print leaf nodes from preorder traversal of BST | Medium | Open ↗ | — | |
| Delete nodes greater than k | Medium | Open ↗ | — | |
| Balance a Binary Search Tree | Medium | Open ↗ | — | |
| Merge two BST 's | Hard | Open ↗ | — | |
| Fixing Two nodes of a BST | Hard | Open ↗ | — | |
| Fixing Two swapped nodes of a BST | Hard | Open ↗ | — | |
| Sorted Link List to BST | Hard | Open ↗ | — | |
| Shortest Range In BST | Hard | Open ↗ | — |
Heaps
0 / 36
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Implement a Maxheap/MinHeap using arrays and recursion. | — | See source ↗ | — | |
| Height of Heap | Easy | Open ↗ | — | |
| Relative Ranks | Easy | Open ↗ | — | |
| Last Stone Weight | Easy | Open ↗ | — | |
| Profit Maximisation | Easy | Open ↗ | — | |
| Maximum Product of Two Elem | Easy | Open ↗ | — | |
| Largest Number After Digit Swaps by Parity | Easy | Open ↗ | — | |
| Minimum Amount of Time to Fil | Easy | Open ↗ | — | |
| Take Gifts From the Richest P | Easy | Open ↗ | — | |
| Minimum Cost of ropes | Easy | Open ↗ | — | |
| Sum of elements between k1'th and k2'th smallest elements | Easy | Open ↗ | — | |
| Merge two binary Max heaps | Easy | Open ↗ | — | |
| Maximum distinct elements after removing K elements | Easy | Open ↗ | — | |
| Gadgets of Doraland | Easy | Open ↗ | — | |
| Merge K sorted arrays! | Easy | Open ↗ | — | |
| Magician and Chocolates | Easy | Open ↗ | — | |
| Heap Sort | Medium | Open ↗ | — | |
| k largest elements | Medium | Open ↗ | — | |
| Kth largest element in a stream | Medium | Open ↗ | — | |
| Is Binary Tree Heap | Medium | Open ↗ | — | |
| Kth element in Matrix | Medium | Open ↗ | — | |
| Huffman Encoding | Medium | Open ↗ | — | |
| K-th Smallest Prime Fraction | Medium | Open ↗ | — | |
| Exam Room | Medium | Open ↗ | — | |
| Rearrange characters | Medium | Open ↗ | — | |
| BST to max heap | Medium | Open ↗ | — | |
| Design Twitter | Medium | Open ↗ | — | |
| Minimum increment/decrement to make array non-Increasing | Medium | Open ↗ | — | |
| Find median in a stream | Hard | Open ↗ | — | |
| Smallest range in K lists | Hard | Open ↗ | — | |
| Reachable Nodes In Subdivided Graph | Hard | Open ↗ | — | |
| Ways to form Max Heap | Hard | Open ↗ | — | |
| Maximum Sum Combinations | Hard | Open ↗ | — | |
| Dinner Plate Stacks | Hard | Open ↗ | — | |
| Construct Target Array With | Hard | Open ↗ | — | |
| Minimum Time to Visit a Cell In a Grid | Hard | Open ↗ | — |
Greedy
0 / 46
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Bulbs | Easy | Open ↗ | — | |
| Ishaan Loves Chocolates | Easy | Open ↗ | — | |
| Assign Mice to Holes | Easy | Open ↗ | — | |
| Majority Element | Easy | Open ↗ | — | |
| Highest Product | Easy | Open ↗ | — | |
| Swap and Maximize | Easy | Open ↗ | — | |
| Good or Bad string | Easy | Open ↗ | — | |
| N meetings in one room | Easy | Open ↗ | — | |
| Longest Palindrome | Easy | Open ↗ | — | |
| Assign Cookies | Easy | Open ↗ | — | |
| Can Place Flowers | Easy | Open ↗ | — | |
| Valid Palindrome II | Easy | Open ↗ | — | |
| Minimum Cost to Move Chips | Easy | Open ↗ | — | |
| Raju and coins | Easy | Open ↗ | — | |
| Huffman Decoding | Easy | Open ↗ | — | |
| Huffman Decoding-1 | Easy | Open ↗ | — | |
| Largest number with given sum | Easy | Open ↗ | — | |
| Disjoint Intervals | Medium | Open ↗ | — | |
| Meeting rooms | Medium | Open ↗ | — | |
| Minimum number of jumps | Medium | Open ↗ | — | |
| Majority Element | Medium | Open ↗ | — | |
| Minimize the Heights I | Medium | Open ↗ | — | |
| Minimize the Heights II | Medium | Open ↗ | — | |
| Minimum Platforms | Medium | Open ↗ | — | |
| Fractional Knapsack | Medium | Open ↗ | — | |
| Page Faults in LRU | Medium | Open ↗ | — | |
| Valid Compressed String | Medium | Open ↗ | — | |
| String rp or pr | Medium | Open ↗ | — | |
| Coin Piles | Medium | Open ↗ | — | |
| Police and Thieves | Medium | Open ↗ | — | |
| Maximum number of events that can be attended | Medium | Open ↗ | — | |
| Water the plants | Medium | Open ↗ | — | |
| Binary Searchable elements | Medium | Open ↗ | — | |
| Decrease Elements To Make A | Medium | Open ↗ | — | |
| Minimum Cost to Move Chips to The Same Position | Medium | Open ↗ | — | |
| Largest Permutation | Hard | Open ↗ | — | |
| Distribute Candy | Hard | Open ↗ | — | |
| Seats | Hard | Open ↗ | — | |
| Gas Station | Hard | Open ↗ | — | |
| Candy | Hard | Open ↗ | — | |
| Patching Array | Hard | Open ↗ | — | |
| Strong Password Checker | Hard | Open ↗ | — | |
| IPO | Hard | Open ↗ | — | |
| Super Washing Machines | Hard | Open ↗ | — | |
| Course Schedule III | Hard | Open ↗ | — | |
| Stamping The Sequence | Hard | Open ↗ | — |
BackTracking
0 / 27
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Find all possible paths from top to bottom | Easy | Open ↗ | — | |
| Combinations | Easy | Open ↗ | — | |
| Binary Tree Paths | Easy | Open ↗ | — | |
| Gray Code | Easy | Open ↗ | — | |
| Letter Phone | Easy | Open ↗ | — | |
| Generate all Parentheses II | Easy | Open ↗ | — | |
| Permutation with Spaces | Easy | Open ↗ | — | |
| Binary Watch | Easy | Open ↗ | — | |
| Generate IP Addresses | Medium | Open ↗ | — | |
| Sudoku | Medium | Open ↗ | — | |
| Permutations | Medium | Open ↗ | — | |
| Maximal String | Medium | Open ↗ | — | |
| Kth Permutation Sequence | Medium | Open ↗ | — | |
| Palindrome Partitioning | Medium | Open ↗ | — | |
| Permutations of a given string | Medium | Open ↗ | — | |
| M-Coloring Problem | Medium | Open ↗ | — | |
| Combination Sum | Medium | Open ↗ | — | |
| Rat in a Maze Problem - I | Medium | Open ↗ | — | |
| Largest number in K swaps | Medium | Open ↗ | — | |
| Unique Subsets | Medium | Open ↗ | — | |
| Generate Parentheses | Medium | Open ↗ | — | |
| Rat Maze With Multiple Jumps | Medium | Open ↗ | — | |
| Coins and Game | Medium | Open ↗ | — | |
| NQueens | Hard | Open ↗ | — | |
| 24 Game | Hard | Open ↗ | — | |
| Maximum Good People Based on Statements | Hard | Open ↗ | — | |
| Expression Add Operators | Hard | Open ↗ | — |
Hashing
0 / 29
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| First Repeating element | Easy | Open ↗ | — | |
| 2 Sum | Easy | Open ↗ | — | |
| Union of two arrays | Easy | Open ↗ | — | |
| First element to occur k times | Easy | Open ↗ | — | |
| Diffk II | Easy | Open ↗ | — | |
| Longest Substring Without Repeat | Easy | Open ↗ | — | |
| Pairs With Given Xor | Easy | Open ↗ | — | |
| Sum of f(a[i], a[j]) over all pairs in an array of n integers | Easy | Open ↗ | — | |
| Substrings with same first and last characters | Easy | Open ↗ | — | |
| Largest subarray with 0 sum | Easy | Open ↗ | — | |
| Count distinct elements in every window | Easy | Open ↗ | — | |
| Largest subarray of 0's and 1's | Easy | Open ↗ | — | |
| Longest consecutive subsequence | Medium | Open ↗ | — | |
| Colorful Number | Medium | Open ↗ | — | |
| Subarray with B odd numbers | Medium | Open ↗ | — | |
| An Increment Problem | Medium | Open ↗ | — | |
| Substring Concatenation | Medium | Open ↗ | — | |
| Copy List | Medium | Open ↗ | — | |
| Triplet Sum in Array | Medium | Open ↗ | — | |
| Nuts and Bolts Problem | Medium | Open ↗ | — | |
| Subarrays with equal 1s and 0s | Medium | Open ↗ | — | |
| Longest subarray with sum divisible by K | Medium | Open ↗ | — | |
| Equal 0, 1 and 2 | Medium | Open ↗ | — | |
| Points on the Straight Line | Hard | Open ↗ | — | |
| Fraction | Hard | Open ↗ | — | |
| Window String | Hard | Open ↗ | — | |
| 4 Sum | Hard | Open ↗ | — | |
| Two out of Three | Hard | Open ↗ | — | |
| Joey doesn't share food | Hard | Open ↗ | — |
Graphs
0 / 63
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| BFS of graph | Easy | Open ↗ | — | |
| DFS of Graph | Easy | Open ↗ | — | |
| Shortest path from 1 to n | Easy | Open ↗ | — | |
| Print adjacency list | Easy | Open ↗ | — | |
| Maximum Weight Node | Easy | Open ↗ | — | |
| Union-Find | Easy | Open ↗ | — | |
| Eulerian Path in an Undirected Graph | Easy | Open ↗ | — | |
| Find the Town Judge | Easy | Open ↗ | — | |
| Find Center of Star Graph | Easy | Open ↗ | — | |
| Path with good nodes! | Easy | Open ↗ | — | |
| Largest Distance between nodes of a Tree | Easy | Open ↗ | — | |
| Two teams? | Easy | Open ↗ | — | |
| Region in BinaryMatrix | Easy | Open ↗ | — | |
| Level Order | Easy | Open ↗ | — | |
| Black Shapes | Easy | Open ↗ | — | |
| Detect cycle in an undirected graph | Medium | Open ↗ | — | |
| Detect cycle in a directed graph | Medium | Open ↗ | — | |
| Topological sort | Medium | Open ↗ | — | |
| Bipartite Graph | Medium | Open ↗ | — | |
| Implementing Dijkstra Algorithm | Medium | Open ↗ | — | |
| Minimum Spanning Tree(Kruksal and Prims) | Medium | Open ↗ | — | |
| Strongly Connected Components (Kosaraju's Algo) | Medium | Open ↗ | — | |
| Distance from the Source (Bellman-Ford Algorithm) | Medium | Open ↗ | — | |
| Euler circuit and Path | Medium | Open ↗ | — | |
| Rotten Oranges | Medium | Open ↗ | — | |
| Steps by Knight | Medium | Open ↗ | — | |
| Flood fill Algorithm | Medium | Open ↗ | — | |
| Find the number of islands | Medium | Open ↗ | — | |
| Shortest Source to Destination Path | Medium | Open ↗ | — | |
| Unit Area of largest region of 1's | Medium | Open ↗ | — | |
| Negative weight cycle | Medium | Open ↗ | — | |
| Circle of strings | Medium | Open ↗ | — | |
| Number of Provinces | Medium | Open ↗ | — | |
| Knight Walk | Medium | Open ↗ | — | |
| Bridge edge in a graph | Medium | Open ↗ | — | |
| Hamiltonian Path | Medium | Open ↗ | — | |
| Replace O's with X's | Medium | Open ↗ | — | |
| Shortest path in Directed Acyclic Graph | Medium | Open ↗ | — | |
| Word Search | Medium | Open ↗ | — | |
| Course Schedule | Medium | Open ↗ | — | |
| Maximum Bipartite Matching | Medium | Open ↗ | — | |
| Number of Ways to Arrive at Destination | Medium | Open ↗ | — | |
| Water Connection Problem | Medium | Open ↗ | — | |
| Covid Spread | Medium | Open ↗ | — | |
| Euler Circuit in an Undirected Graph | Medium | Open ↗ | — | |
| Maximum Bipartite Matching | Medium | Open ↗ | — | |
| Water Flow | Medium | Open ↗ | — | |
| Possible paths between 2 vertices | Medium | Open ↗ | — | |
| X Total Shapes | Medium | Open ↗ | — | |
| Prerequisite Tasks | Medium | Open ↗ | — | |
| Find whether path exist | Medium | Open ↗ | — | |
| Strongly connected component (Tarjans's Algo) | Hard | Open ↗ | — | |
| Alien Dictionary | Hard | Open ↗ | — | |
| Minimum Cost Path | Hard | Open ↗ | — | |
| Articulation Point - I | Hard | Open ↗ | — | |
| Word Ladder I | Hard | Open ↗ | — | |
| Largest Sum Cycle | Hard | Open ↗ | — | |
| Shortest Path Using Atmost One Curved Edge | Hard | Open ↗ | — | |
| Word Ladder II | Hard | Open ↗ | — | |
| Assignment Problem | Hard | Open ↗ | — | |
| Articulation Point - II | Hard | Open ↗ | — | |
| Critical Connections | Hard | Open ↗ | — | |
| Find number of closed islands | Hard | Open ↗ | — |
Dynamic Programming
0 / 123
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Print first n Fibonacci Numbers | Easy | Open ↗ | — | |
| Count numbers containing 4 | Easy | Open ↗ | — | |
| Nth Fibonacci Number | Easy | Open ↗ | — | |
| Stock buy and sell | Easy | Open ↗ | — | |
| Count number of hops | Easy | Open ↗ | — | |
| Coin ChangeProblem | Medium | Open ↗ | — | |
| Number of Coins | Medium | Open ↗ | — | |
| 0-1 Knapsack | Medium | Open ↗ | — | |
| Tushar's Birthday Party | Medium | Open ↗ | — | |
| Matrix Chain Multiplication | Medium | Open ↗ | — | |
| Program for nth Catalan Number | Medium | Open ↗ | — | |
| Kadane's Algorithm | Medium | Open ↗ | — | |
| Longest Common Subsequence | Medium | Open ↗ | — | |
| Longest Increasing Subsequence | Medium | Open ↗ | — | |
| Longest Common Substring | Medium | Open ↗ | — | |
| Longest Repeating Subsequence | Medium | Open ↗ | — | |
| Longest Palindromic Subsequence | Medium | Open ↗ | — | |
| Longest Arithmetic Progression | Medium | Open ↗ | — | |
| Longest Bitonic subsequence | Medium | Open ↗ | — | |
| Longest Common Increasing Subsequence | Medium | Open ↗ | — | |
| Subset Sum Problem | Medium | Open ↗ | — | |
| Count Palindromic Subsequences | Medium | Open ↗ | — | |
| Longest Palindrome in a String | Medium | Open ↗ | — | |
| Egg Dropping Puzzle | Medium | Open ↗ | — | |
| Floyd Warshall | Medium | Open ↗ | — | |
| Word Break | Medium | Open ↗ | — | |
| Palindrome Partitioning II | Medium | Open ↗ | — | |
| Shortest Common Supersequence | Medium | Open ↗ | — | |
| LCS of three strings | Medium | Open ↗ | — | |
| Box Stacking | Medium | Open ↗ | — | |
| Count of Subarrays | Medium | Open ↗ | — | |
| Longest alternating subsequence | Medium | Open ↗ | — | |
| Count Cyclic Paths | Medium | Open ↗ | — | |
| Ways to sum to N | Medium | Open ↗ | — | |
| Maximum Sum Subsequence of length k | Medium | Open ↗ | — | |
| Find length of longest subsequence | Medium | Open ↗ | — | |
| Number of palindromic strings | Medium | Open ↗ | — | |
| Palindromic Strings | Medium | Open ↗ | — | |
| Trapping Rain Water | Medium | Open ↗ | — | |
| Maximum Product Subarray | Medium | Open ↗ | — | |
| nCr | Medium | Open ↗ | — | |
| Maximize The Cut Segments | Medium | Open ↗ | — | |
| Edit Distance | Medium | Open ↗ | — | |
| Partition Equal Subset Sum | Medium | Open ↗ | — | |
| Count ways to reach the n'th stair | Medium | Open ↗ | — | |
| Stickler Thief | Medium | Open ↗ | — | |
| Job Sequencing Problem | Medium | Open ↗ | — | |
| Perfect Sum Problem | Medium | Open ↗ | — | |
| Maximum sum increasing subsequence | Medium | Open ↗ | — | |
| Max length chain | Medium | Open ↗ | — | |
| Maximum path sum in matrix | Medium | Open ↗ | — | |
| Regular Expression Match | Medium | Open ↗ | — | |
| Smallest sequence with given Primes | Medium | Open ↗ | — | |
| Wildcard Pattern Matching | Medium | Open ↗ | — | |
| Tiling With Dominoes | Medium | Open ↗ | — | |
| Paint House! | Medium | Open ↗ | — | |
| Intersecting Chords in a Circle | Medium | Open ↗ | — | |
| N digit numbers with digit sum S | Medium | Open ↗ | — | |
| Kth Manhattan Distance Neighbourhood | Medium | Open ↗ | — | |
| Best Time to Buy and Sell Stock atmost B times | Medium | Open ↗ | — | |
| Best Time to Buy and Sell Stocks III | Medium | Open ↗ | — | |
| Longest valid Parentheses | Medium | Open ↗ | — | |
| Rod Cutting | Medium | Open ↗ | — | |
| Max Rectangle in Binary Matrix | Medium | Open ↗ | — | |
| Maximum Size Square Sub-matrix | Medium | Open ↗ | — | |
| Maximum Path in Triangle | Medium | Open ↗ | — | |
| Min Sum Path in Matrix | Medium | Open ↗ | — | |
| Coin Sum Infinite | Medium | Open ↗ | — | |
| Arrange II | Medium | Open ↗ | — | |
| Interleaved Strings | Medium | Open ↗ | — | |
| Consecutive 1's not allowed | Medium | Open ↗ | — | |
| Unique BST's | Medium | Open ↗ | — | |
| Minimum number of Coins | Medium | Open ↗ | — | |
| Maximum Tip Calculator | Medium | Open ↗ | — | |
| Snake and Ladder Problem | Medium | Open ↗ | — | |
| Special Keyboard | Medium | Open ↗ | — | |
| Minimum cost to fill given weight in a bag | Medium | Open ↗ | — | |
| Count ways to N'th Stair(Order does not matter) | Medium | Open ↗ | — | |
| Distinct occurrences | Medium | Open ↗ | — | |
| Count subsequences of type a^i, b^j, c^k | Medium | Open ↗ | — | |
| Special Matrix | Medium | Open ↗ | — | |
| Number of ways | Medium | Open ↗ | — | |
| Distinct Coloring | Medium | Open ↗ | — | |
| Shortest XY distance in Grid | Medium | Open ↗ | — | |
| Water Overflow | Medium | Open ↗ | — | |
| Count possible ways to construct buildings | Medium | Open ↗ | — | |
| Number of paths in a matrix with k coins | Medium | Open ↗ | — | |
| Buy and Sell a Share at most twice | Medium | Open ↗ | — | |
| Minimum steps to destination | Medium | Open ↗ | — | |
| Player with max score | Medium | Open ↗ | — | |
| Cutting Binary String | Medium | Open ↗ | — | |
| Two water Jug problem | Medium | Open ↗ | — | |
| Min cut Square | Medium | Open ↗ | — | |
| Maximum sum of elements not part of LIS | Medium | Open ↗ | — | |
| Count of AP Subsequences | Medium | Open ↗ | — | |
| Pascal's Triangle | Medium | Open ↗ | — | |
| Pascal's Triangle II | Medium | Open ↗ | — | |
| Best Time to Buy and Sell Stock IV | Medium | Open ↗ | — | |
| House Robber | Medium | Open ↗ | — | |
| House Robber II | Medium | Open ↗ | — | |
| Last Stone Weight II | Medium | Open ↗ | — | |
| Predict the Winner | Medium | Open ↗ | — | |
| Palindromic Partitioning | Hard | Open ↗ | — | |
| Minimum sum partition | Hard | Open ↗ | — | |
| Smallest window in a string containing all the characters of another string | Hard | Open ↗ | — | |
| The Painter's Partition Problem-II | Hard | Open ↗ | — | |
| Word Wrap | Hard | Open ↗ | — | |
| Partition array to K subsets | Hard | Open ↗ | — | |
| Word Break - Part 2 | Hard | Open ↗ | — | |
| Maximum Profit | Hard | Open ↗ | — | |
| Maximum Number of coins | Hard | Open ↗ | — | |
| Minimum Points To Reach Destination | Hard | Open ↗ | — | |
| Count occurrences of a given word in a 2-d array | Hard | Open ↗ | — | |
| Print all LCS sequences | Hard | Open ↗ | — | |
| Find all possible palindromic partitions of a String | Hard | Open ↗ | — | |
| Strictly Increasing Array | Hard | Open ↗ | — | |
| Brackets in Matrix Chain Multiplication | Hard | Open ↗ | — | |
| Longest Zig-Zag Sub Sequence | Hard | Open ↗ | — | |
| Longest Increasing Path in a Matrix | Hard | Open ↗ | — | |
| Burst Balloons | Hard | Open ↗ | — | |
| Russian Doll Envelopes | Hard | Open ↗ | — | |
| Number of Ways to Stay in the | Hard | Open ↗ | — | |
| Maximum Sum BST in Binary | Hard | Open ↗ | — |
Segment Tree
0 / 9
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| XOR of a given range | Easy | Open ↗ | — | |
| Maximum prefix sum for a given range | Easy | Open ↗ | — | |
| Range Minimum Query | Medium | Open ↗ | — | |
| Nitika and her queries | Medium | Open ↗ | — | |
| Smallest Subarray GCD | Medium | Open ↗ | — | |
| Element left after performing alternate OR & XOR operation | Medium | Open ↗ | — | |
| Array Partition | Hard | Open ↗ | — | |
| Akku and Arrays | Hard | Open ↗ | — | |
| Greater or Less | Hard | Open ↗ | — |
Trie
0 / 14
| Done | Problem | Level | Practice | Video |
|---|---|---|---|---|
| Unique rows in boolean matrix | Easy | Open ↗ | — | |
| Trie | (Insert and Search) | Medium | Open ↗ | — | |
| Word Boggle | Medium | Open ↗ | — | |
| Most frequent word in an array of strings | Medium | Open ↗ | — | |
| Maximum XOR subarray | Medium | Open ↗ | — | |
| CamelCase Pattern Matching | Medium | Open ↗ | — | |
| Trie | (Delete) | Medium | Open ↗ | — | |
| Word Boggle - II | Medium | Open ↗ | — | |
| Prefix match with other strings | Medium | Open ↗ | — | |
| Phone directory | Hard | Open ↗ | — | |
| Palindrome Pairs | Hard | Open ↗ | — | |
| Shortest Unique prefix for every word | Hard | Open ↗ | — | |
| Word Break (Trie) | Hard | Open ↗ | — | |
| Find duplicate rows in a binary matrix | Hard | Open ↗ | — |