Rohit Negi DSA Sheet
An extensive problem set covering DSA topics in depth, from Coder Army.
By Rohit Negi (Coder Army) · 725 Problems
Total Problems: 725Difficulty Levels:BasicEasyMediumHard
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Array Search
Check Equal Arrays
Missing element of AP
Rotate Array by One
Min and Max in Array
Binary Array Sorting
Move all negative elements to end
Missing number
Search a 2D Matrix
Find the fine
Greater on right side
Remove Duplicates Sorted Array
Indexes of Subarray Sum
Sort 0s, 1s and 2s
Equilibrium Point
Peak element
Find Transition Point
Alternate Positive Negative
Union of 2 Sorted Arrays
Three way partitioning
Frogs and Jumps
Min Subsets with Consecutive Numbers
Missing And Repeating
Rearrange Array Alternately
Pythagorean Triplet
Rearrange an array with O(1) extra space
Triplets with Smaller Sum
Boolean Matrix
Row with max 1s
Container With Most Water
Maximum Triplet product
Coins of Geekland
Next Permutation
Rotate Image
Count Primes
Watering Plants
Arithmetic Subarrays
Majority Element
Max Circular Subarray Sum
Subarrays Product Less than K
Maximum subset XOR
Next Smallest Palindrome
Count the number of subarrays
Largest rectangle of 1s with swapping of columns allowed
N/3 Repeat Number
Reverse a String
Strings Rotations of Each Other
Most Frequent Character
Binary String
Anagram of String
Merge two strings
Reverse Words
Palindrome String
Longest Common Prefix of Strings
Roman Number to Integer
Length of Last Word
Longest substring with distinct characters
String Duplicates Removal
Min Number of Flips
Meta Strings
Smallest window containing 0, 1 and 2
Generate Grey Code Sequences
Sum of two large numbers
Length of the longest substring
Longest Prefix Suffix
Smallest distinct window
Case-specific Sorting of Strings
Excel Sheet | Part - 1
Transform String
Remove and Reverse
String formation from substring
Minimum Days
Remove Consecutive Characters
Bulls and Cows
Atoi
Valid Ip Addresses
Integer To Roman
Min Chars to Add for Palindrome
Wildcard string matching
Longest Palindromic Substring in Linear Time
Numbers with one absolute difference
Stringoholics
Power of 2
Justified Text
Sorted Array Search
Last index of One
Count the Zeros
Elements in the Range
Bubble Sort
Insertion Sort
First and last occurrences of x
Count zeros in a sorted matrix
Array Subset
Selection Sort
Floor in a Sorted Array
Radix Sort
Search in a Row-Column sorted matrix
Bitonic Point
Two Repeated Elements
More than n/k Occurrences
Number and the Digit Sum
Find triplets with zero sum
Sort Array II
Sort in specific order
Sort a String
Triplet Family
Merge and Sort
Merging two unsorted arrays in sorted order
Rope Cutting
Make array elements unique
Kth Smallest
Smallest Positive Missing
Sort according to an Array
Square Root
Search in a sorted Matrix
Smallest number with at least n trailing zeroes in factorial
Merge Sort
Quick Sort
Count Inversions
4 Sum - All Quadruples
Minimum Swaps to Sort
Number of pairs
Sort an Array
Sort Elements by Decreasing Frequency
Overlapping Intervals
Find minimum number of Laptops required
LCP
Reach a Number
Heaters
Friends Of Appropriate Ages
Koko Eating Bananas
3Sum
3Sum Closest
Nth Digit
Sort a 2D vector diagonally
Maximum Intersecting Lines
Merge Without Extra Space
Median of the Subarrays
Median of Array
Implement Power Function
WoodCutting Made Easy!
Matrix Median
Allocate Books
Painter's Partition Problem
Red Zone
Max Sum of Rectangle No Larger Than K
Smallest Good Base
House Robber IV
Maximum Gap
Print Linked List
Linked List Insertion At End
Find Length of Linked List
Check If Circular Linked List
Identical Linked Lists
Insert in a Sorted List
Insert in Middle of Linked List
Delete in a Doubly Linked List
Reverse a Doubly Linked List
Delete Alternate Nodes
Find the Sum of Last N nodes of the Linked List
Find n/k th node in Linked list
Detect Loop in linked list
Move Last Element to Front of a Linked List
Kth from End of Linked List
Middle of a Linked List
Reverse a linked list
Remove Duplicates from a Sorted Linked List
Delete without head pointer
Remove duplicates from an unsorted linked list
Delete in a Singly Linked List
Sort a linked list of 0s, 1s and 2s
Find length of Loop
Intersection Sorted Linked Lists
Pairwise swap elements of a linked list
Insert in Sorted Circular Linked List
Count Pairs whose sum is equal to X
Intersection of Two Linked Lists
Split a Linked List into two halves
Union of Two Linked Lists
Linked List Matrix
XOR Linked List
Remove loop in Linked List
Intersection in Y Shaped Lists
Palindrome Linked List
Rotate a Linked List
Merge two sorted linked lists
Delete nodes having greater value on right
Merge Sort for Linked List
Rearrange a linked list
Prime List
Longest Palindrome in Linked List
Reverse alternate nodes in Link List
Merge Sort on Doubly Linked List
Quick Sort on Linked List
QuickSort on Doubly Linked List
Remove all occurences of duplicates in a linked list
Sort for Singly Linked List
Reverse Alternate K Nodes
Linked List Cycle II
LRU Cache
Flatten a Multilevel Doubly Linked List
Clone List with Next and Random
Reorder List
Reverse a sublist of a linked list
LFU Cache
Reverse Nodes in k-Group
Design Skiplist
Subtraction in Linked List
Next Smaller Element
Implement stack using array
Stack using Linked List
Pairwise Consecutive Elements
Parenthesis Checker
Sort a stack
Delete Mid of a Stack
Maximum Difference
Print Bracket Number
Max Score from Subarray Mins
String Manipulation
Make the array beautiful
Next Greater Element I
Baseball Game
Backspace String Compare
Next Greater Element
Get Min from Stack
The Celebrity Problem
Smaller on Left
Asteroid Collision
Remove K Digits
Valid Expression
Max Equal sum of 3 Stacks
MAXSPPROD
Decode String
Evaluate Expression
Redundant Braces
Next Greater Element II
Clumsy Factorial
Histogram Max Rectangular Area
Max of min for every window size
IPL 2021 - Final
IPL 2021 - Match Day 6 - Semi Final
Rain Water Trapped
Simplify Directory Path
Basic Calculator
Create Maximum Number
Tag Validator
Max Chunks To Make Sorted II
Queue Push & Pop
Queue Reversal
Queue Using Array
Queue using Linked List
Generate Binary Numbers
Stack using Queue
Queue using two Stacks
Reverse first K of a Queue
Deque Implementations
Next Right Node
First Unique Character in a String
Number of Recent Calls
Time Needed to Buy Tickets
Stream First Non-repeating
Gas Station
Count the Reversals
Validate Stack Operations
Operations on PriorityQueue
Design Circular Deque
First non-repeating character in a stream of characters
Sliding Window Maximum
Stamping The Sequence
Minimum Number of K Consecutive Bit Flips
Count Subarrays With Fixed Bounds
Inorder Traversal
Preorder Traversal
Postorder Traversal
Count Leaves in Binary Tree
Size of Binary Tree
Sum of Binary Tree
Count Non-Leaf Nodes in Tree
Left View of Binary Tree
Right View of Binary Tree
Height of Binary Tree
Root to leaf paths sum
Balanced Tree Check
Identical Trees
Level order traversal
Level Order in spiral form
Mirror Tree
Nodes without a Sibling
Maximum Depth Of Binary Tree
Shortest distance in infinite tree
Largest value in each level
Perfect Binary Tree
Nodes at Odd Levels
Remove Half Nodes
Parent of Max GCD Siblings in a Binary Tree
Maximum Node Level
Deletion in a Binary Tree
Check if two Nodes are Cousins
Vertical Order traversal of Binary Tree
Diagonal Traversal
Flatten Binary Tree to Linked List
Merge two Binary Tree
Maximum Edge Removal
Populate Next Right Pointers Tree
Burn a Tree
Tree Boundary Traversal
Diameter of a Binary Tree
Sum Tree
Top View of Binary Tree
Bottom View of Binary Tree
LCA in Binary Tree
Maximum difference between node and its ancestor
Serialize and deserialize a binary tree
Maximum Non-Adjacent Nodes Sum
Foldable Binary Tree
Construct Binary Tree from Parent Array
Linked List to Binary Tree
Check Mirror in N-ary tree
Iterative Inorder
Iterative Postorder
Print Nodes having K leaves
Print Binary Tree levels in sorted order
Nodes at given distance in binary tree
Burning Tree
Check if all levels of two trees are anagrams or not
Binary Tree to DLL
Max Path Sum 2 Special Nodes
Scrambled String
Check Tree Traversal
Corona Vaccine
Recover a Tree From Preorder Traversal
Search a node in BST
Minimum element in BST
Check for BST
Insert a node in a BST
Kth largest element in BST
Inorder Traversal and BST
Binary Tree to BST
Median of BST
Kth Smallest Element In Tree
BST Iterator
2-Sum Binary Tree
Find Common Nodes in two BSTs
Array to BST
Inorder Successor in BST
BST Keys in a Range
BST with Dead End
Find Sum Pairs Across Two BSTs
Sum of k smallest elements in BST
Minimum Distance Between BST Nodes
Normal BST to Balanced BST
Construct BST from Postorder
Recover Binary Search Tree
Valid BST from Preorder
k-th Smallest in BST
Delete a node from BST
Largest BST
Predecessor and Successor
Preorder to BST
Closest in BST
Ceil in BST
Preorder Traversal and BST
Bheem Wants Ladoos
Minimum Absolute Difference In BST
Valentine Sum
Pairs violating the BST property
Remove BST keys outside given range
Print leaf nodes from preorder traversal of BST
Delete nodes greater than k
Balance a Binary Search Tree
Merge two BST 's
Fixing Two nodes of a BST
Fixing Two swapped nodes of a BST
Sorted Linked List to BST
Shortest Range In BST
Binary Heap Operations
Height of Heap
Relative Ranks
Last Stone Weight
Profit Maximisation
Maximum Product of Two Elements in an Array
Largest Number After Digit Swaps by Parity
Minimum Amount of Time to Fill Cups
Take Gifts From the Richest Pile
Minimum Cost of ropes
Sum of elements between k1'th and k2'th smallest elements
Merge two binary Max heaps
Maximum distinct elements after removing K elements
Gadgets of Doraland
Merge K sorted arrays!
Magician and Chocolates
Heap Sort
k largest elements
Kth Largest in a Stream
Is Binary Tree Heap
Kth smallest element in a Matrix
Huffman Encoding
K-th Smallest Prime Fraction
Exam Room
Rearrange characters
BST to max heap
Design Twitter
Minimum increment/decrement to make array non-Increasing
Find median in a stream
Smallest range in K lists
Reachable Nodes In Subdivided Graph
Ways to form Max Heap
Maximum Sum Combinations
Dinner Plate Stacks
Construct Target Array With Multiple Sums
Minimum Time to Visit a Cell In a Grid
Bulbs
Ishaan Loves Chocolates
Assign Mice to Holes
Majority Element
Highest Product
Swap and Maximize
Good or Bad string
N meetings in one room
Longest Palindrome
Assign Cookies
Can Place Flowers
Valid Palindrome II
Minimum Cost to Move Chips
Raju and coins
Huffman Decoding
Huffman Decoding-1
Largest number with given sum
Disjoint Intervals
Meeting rooms
Minimum Jumps
Majority Element
Minimize the Heights I
Minimize the Heights II
Minimum Platforms
Fractional Knapsack
Page Faults in LRU
Valid Compressed String
String rp or pr
Coin Piles
Police and Thieves
Maximum number of events that can be attended
Closest Similar Elements
Binary Searchable elements
Decrease Elements To Make Array Zigzag
Largest Permutation
Distribute Candy
Seats
Gas Station
Candy
Patching Array
Strong Password Checker
IPO
Super Washing Machines
Course Schedule III
Stamping The Sequence
Find all possible paths from top to bottom
Combinations
Binary Tree Paths
Gray Code
Letter Phone
Generate all Parentheses II
Permutation with Spaces
Binary Watch
Generate IP Addresses
Sudoku
Permutations
Maximal String
Kth Permutation Sequence
Palindrome Partitioning
Permutations of a String
M-Coloring Problem
Target Sum Combinations
Rat in a Maze
Largest number in K swaps
Unique Subsets
Generate Parentheses
Rat Maze With Multiple Jumps
Coins and Game
NQueens
24 Game
Maximum Good People Based on Statements
Expression Add Operators
First Repeating element
2 Sum
Union of Arrays with Duplicates
At Least K Occurrences
Diffk II
Longest Substring Without Repeat
Pairs With Given Xor
Sum of f(a[i], a[j]) over all pairs in an array of n integers
Substrings with same first and last characters
Largest subarray with 0 sum
Count distinct elements in every window
Largest subarray of 0's and 1's
Longest Consecutive Subsequence
Colorful Number
Subarray with B odd numbers
An Increment Problem
Substring Concatenation
Copy List
Triplet Sum in Array
Nuts and Bolts Problem
Subarrays with equal 1s and 0s
Longest subarray with sum divisible by K
Equal 0, 1 and 2
Points on the Straight Line
Fraction
Window String
4 Sum
Two out of Three
Joey doesn't share food
BFS of graph
DFS of Graph
Shortest path from 1 to n
Print adjacency list
Maximum Weight Node
Union-Find
Eulerian Path in an Undirected Graph
Find the Town Judge
Find Center of Star Graph
Path with good nodes!
Largest Distance between nodes of a Tree
Two teams?
Region in BinaryMatrix
Level Order
Black Shapes
Undirected Graph Cycle
Directed Graph Cycle
Topological Sort
Bipartite Graph
Dijkstra Algorithm
Minimum Spanning Tree
Strongly Connected
Bellman-Ford
Euler circuit and Path
Rotten Oranges
Steps by Knight
Flood fill Algorithm
Find the number of islands
Shortest Source to Destination Path
Unit Area of largest region of 1's
Negative weight cycle
Circle of strings
Number of Provinces
Knight Walk
Bridge edge in a graph
Hamiltonian Path
Replace O's with X's
Shortest path in Directed Acyclic Graph
Word Search
Course Schedule II
Maximum Bipartite Matching
Number of Ways to Arrive at Destination
Water Connection Problem
Covid Spread
Euler Circuit in an Undirected Graph
Maximum Bipartite Matching
Water Flow
Possible paths between 2 vertices
X Total Shapes
Prerequisite Tasks
Find whether path exist
Strongly connected component (Tarjans's Algo)
Alien Dictionary
Minimum Cost Path
Articulation Point - I
Word Ladder I
Largest Sum Cycle
Shortest Path Using Atmost One Curved Edge
Word Ladder II
Assignment Problem
Articulation Point - II
Find all Critical Connections in the Graph
Find number of closed islands
First n Fibonacci
Count numbers containing 4
Nth Fibonacci Number
Stock buy and sell
Count number of hops
Coin Change (Count Ways)
Coin Change (Minimum Coins)
0-1 Knapsack
Tushar's Birthday Party
Matrix Chain Multiplication Dp 8
Program Nth Catalan Number
Kadane's Algorithm
Longest Common Subsequence
Longest Increasing Subsequence
Longest Common Substring
Longest Repeating Subsequence
Longest Palindromic Subsequence
Longest Arithmetic Subsequence
Longest Bitonic subsequence
Longest Common Increasing Subsequence
Subset Sum Problem
Count Palindromic Subsequences
Longest Palindrome in a String
Egg Dropping Puzzle
Floyd Warshall
Word Break
Palindrome Partitioning II
Shortest Common Supersequence
LCS of three strings
Box Stacking
Count of Subarrays
Longest alternating subsequence
Count Cyclic Paths
Ways to sum to N
Maximum Sum Subsequence of length k
Find length of longest subsequence
Number of palindromic strings
Palindromic Strings
Trapping Rain Water
Maximum Product Subarray
nCr
Maximize The Cut Segments
Edit Distance
Partition Equal Subset Sum
Ways to Reach the n'th Stair
Stickler Thief
Job Sequencing Problem
Perfect Sum Problem
Max Sum Increasing Subsequence
Sum Except First and Last
Maximum path sum in matrix
Regular Expression Match
Smallest sequence with given Primes
Wildcard Pattern Matching
Tiling With Dominoes
Paint House!
Intersecting Chords in a Circle
N digit numbers with digit sum S
Kth Manhattan Distance Neighbourhood
Best Time to Buy and Sell Stock atmost B times
Best Time to Buy and Sell Stocks III
Longest valid Parentheses
Rod Cutting
Max Rectangle in Binary Matrix
Maximum Size Square Sub-matrix
Maximum Path in Triangle
Min Sum Path in Matrix
Coin Sum Infinite
Arrange II
Interleaved Strings
Consecutive 1's not allowed
Unique BST's
Minimum number of Coins
Maximum Tip Calculator
Snake and Ladder Problem
Special Keyboard
Minimum cost to fill given weight in a bag
Count ways to N'th Stair(Order does not matter)
Distinct occurrences
Count subsequences of type a^i, b^j, c^k
Special Matrix
Number of ways
Paint N Houses
Shortest XY distance in Grid
Water Overflow
Count possible ways to construct buildings
Number of paths in a matrix with k coins
Stock Buy and Sell – Max 2 Transactions Allowed
Minimum steps to destination
Player with max score
Cutting Binary String
Two water Jug problem
Min cut Square
Maximum sum of elements not part of LIS
Count of AP Subsequences
Pascal's Triangle
Pascal's Triangle II
Best Time to Buy and Sell Stock IV
House Robber
House Robber II
Last Stone Weight II
Predict the Winner
Palindromic Partitioning
Minimum sum partition
Smallest window containing all characters
The Painter's Partition Problem-II
Word Wrap
Partition array to k subsets
Word Break - 2
Stock Buy and Sell – Max K Transactions Allowed
Maximum Number of coins
Minimum Points To Reach Destination
Count occurrences of a given word in a 2-d array
Print all LCS sequences
All Palindromic Partitions
Strictly Increasing Array
Brackets in Matrix Chain Multiplication
Longest Zig-Zag Sub Sequence
Longest Increasing Path in a Matrix
Burst Balloons
Russian Doll Envelopes
Number of Ways to Stay in the Same Place After Some Steps
Maximum Sum BST in Binary Tree
XOR of a given range
Maximum prefix sum for a given range
Range Minimum Query
Array Sum Excluding Subarrays
Smallest Subarray GCD
Element left after performing alternate OR & XOR operation
Array Partition
Akku and Arrays
Greater or Less
Unique rows in boolean matrix
Implement Trie
Word Boggle
Most frequent word in an array of strings
Maximum XOR subarray
CamelCase Pattern Matching
Trie | (Delete)
Open the gates
Prefix match with other strings
Phone directory
Palindrome Pairs
Shortest Unique prefix for every word
Word Break (Trie)
Find duplicate rows in a binary matrix
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An extensive data structures and algorithms problem set created by Rohit Negi of Coder Army, covering topics in depth across 17 sections.
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725 problems, the largest of the sheets on this site.
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