Skip to main content

Explore Problems

Pricing Discuss

CodePeet 444 Complete DSA Sheet

Course Contents

Reading & Printing Values

Variable Types & Storage

Conditional Branching

Multi-Way Selection

Introduction to Sequential Data(Arrays & Strings)

Counted Iteration (for)

Conditional Iteration (while)

Functions & Parameter Passing

Complexity Analysis Primer

Nested Loop Patterns

C++ Standard Library Overview

Java Collections Framework

Count Digits of a Number

Palindrome Number

Greatest Common Divisor of 2 numbers

Armstrong Number

Finding All Divisors

Primality Check

Reverse Integer

Recursion via Repeated Printing

Number Series Without Loops

print 1 to N using recursion

print N to 1 using recursion

Sum of First N Natural Numbers

Computing Factorial Recursively

Reverse an Array using recursion

Valid Palindrome

Fibonacci Number

Element Frequency Count

Introduction to Hashing

Frequency of the Most Frequent Element

Bubble Sort with Recursion

Insertion Sort with Recursion

Find Maximum in Array

Second Maximum Without Sorting

Check if Array Is Sorted and Rotated

Remove Duplicates from Sorted Array

Union of Two Arrays

Max Consecutive Ones

Longest Subarray with sum K (Positives)

Longest Subarray with sum K (All Integers)

Majority Element

Best Time to Buy and Sell Stock

Maximum Subarray

Maximum Sum Subarray with Indices

Rearrange Array Elements by Sign

Next Permutation

Longest Consecutive Sequence

Set Matrix Zeroes

Subarray Sum Equals K

Pascal's Triangle

Merge Sorted Array

Majority Element II

Longest Subarray with Zero Sum

Merge Intervals

Maximum Product Subarray

Count subarrays with given XOR

Find Missing and Repeated Values

Inversion Count in Array

Implement Lower Bound

Implement Upper Bound

Search Insert Position

Floor & Ceiling in Sorted Array

Sort Array by Increasing Frequency

Rotation Count in a Rotated Sorted array

Find First and Last Position of Element in Sorted Array

Search in Rotated Sorted Array

Search in Rotated Sorted Array II

Find Minimum in Rotated Sorted Array

Single Element in a Sorted Array

Find Peak Element

Kth Missing Positive Number

Square Root of an Integer

Find nth root of m

Koko Eating Bananas

Minimum Number of Days to Make m Bouquets

Find the Smallest Divisor Given a Threshold

Capacity To Ship Packages Within D Days

Kth Element of Two Sorted Arrays

Maximize Minimum Distance

Minimize Maximum Pages Allocated

Split Array Largest Sum

Painter's Partition Problem

Minimize Max Distance to Gas Station

Median of Two Sorted Arrays

Row with Most Ones

Search a 2D Matrix

Search a 2D Matrix II

Find a Peak Element II

Median in a row-wise sorted Matrix

Remove Outermost Parentheses

Largest Odd Number in String

Longest Common Prefix

Isomorphic Strings

Reverse Words in a String

Maximum Nesting Depth of the Parentheses

Roman to Integer

Sort Characters By Frequency

String to Integer (atoi)

Substrings with K Distinct Characters

Longest Palindromic Substring

Sum of Beauty of All Substrings

Reverse Words in a String

Linked List Fundamentals

Insertion at a Given Position in a Linked List

Length of a linked list

Search in Linked List

Delete Node in a Linked List

Doubly Linked List Fundamentals

Inserting into a Doubly Linked List

Deleting from a Doubly Linked List

Reversing a Doubly Linked List

Middle of the Linked List

Reverse Linked List

Linked List Cycle

Palindrome Linked List

Intersection of Two Linked Lists

Linked List Cycle II

Cycle Length Detection

Odd Even Linked List

Remove Nth Node From End of List

Delete the Middle Node of a Linked List

Partition a Linked List around a given value

Add 1 to a number represented as linked list

Add Two Numbers

Find pairs with given sum in doubly linked list

Delete all occurrences of a given key in a doubly linked list

Remove duplicates from a sorted doubly linked list

Copy List with Random Pointer

Reverse Nodes in k-Group

Flatten a Multilevel Doubly Linked List

Reverse a Stack Recursively

String to Integer (atoi)

Count Good Numbers

Sort a Stack Recursively

Number of Subsequences That Satisfy the Given Sum Condition

Check if there exists a subsequence with sum K

Generate all binary strings

Generate Parentheses

Understanding Subsequences

Combination Sum

Combination Sum II

Combination Sum III

Letter Combinations of a Phone Number

Palindrome Partitioning

M-Coloring Problem

Expression Add Operators

Bitwise Operations Overview

Divisibility by 3 Check

Counting Set Bits

Toggle Rightmost Unset Bit

XOR-Based Number swap

Divide Two Integers

Minimum Bit Flips to Convert Number

XOR Queries of a Subarray

Two odd Occuring Numbers in an Array

All divisors of a Number

Prime Factorization

Sieve-Based Prime Factorization

Implement stack using array

Queue using Array

Implement Stack using Queues

Implement Queue using Stacks

Stack using Linked List

Implement Queue using Stacks

Valid Parentheses

Infix to Postfix Using Stack

Prefix to Infix Conversion

Prefix to Postfix Conversion

Postfix to Prefix Conversion

Postfix to Infix Conversion

Infix to Prefix Conversion

Next Greater Element I

Previous Smaller Element

Count of Greater Elements to Right

Next Greater Element II

Sum of Subarray Minimums

Asteroid Collision

Sum of Subarray Ranges

Remove K Digits

Trapping Rain Water

Largest Rectangle in Histogram

Maximal Rectangle

Online Stock Span

Sliding Window Maximum

The Celebrity Problem

Longest Substring Without Repeating Characters

Max Consecutive Ones III

Fruit Into Baskets

Longest Repeating Character Replacement

Binary Subarrays With Sum

Count Number of Nice Subarrays

Number of Substrings Containing All Three Characters

Maximum Points You Can Obtain from Cards

Longest Substring with At Most K Distinct Characters

Subarrays with K Different Integers

Minimum Window Substring

Minimum Window Subsequence

Priority Queue via Binary Heap

Min-Heap & Max-Heap Implementation

Validate Heap Property in Array

Convert Min Heap to Max Heap

Sort Nearly Sorted Array

Rank Transform of an Array

Kth Largest Element in an Array

Kth Smallest Element

Hand of Straights

Merge k Sorted Lists

Kth Largest Element in a Stream

Minimum Cost Rope Connection

Top K Frequent Elements

Maximum Sum Combination

Find Median from Data Stream

Lemonade Change

Fractional Knapsack

Valid Parenthesis String

Non-overlapping Intervals

Minimum Railway Platforms

Maximum Profit in Job Scheduling

Shortest Job First Scheduling

Insert Interval

Merge Intervals

Non-overlapping Intervals

Tree Data Structure Basics

Binary Tree Representation

Binary Tree Representation (Java)

Tree Boundary Traversal

Binary Tree Preorder Traversal

Binary Tree Inorder Traversal

Binary Tree Postorder Traversal

All Three Traversals

Binary Tree Level Order Traversal

Maximum Depth of Binary Tree

Balanced Binary Tree

Diameter of Binary Tree

Binary Tree Zigzag Level Order Traversal

Boundary of Binary Tree

Top View of a Binary Tree

Bottom View of Binary Tree

Binary Tree Right Side View

Binary Tree Maximum Path Sum

Vertical Order Traversal of a Binary Tree

Count Complete Tree Nodes

Binary Tree Inorder Traversal

Binary Tree Paths

Lowest Common Ancestor of a Binary Tree

Maximum Width of Binary Tree

All Nodes Distance K in Binary Tree

Conditions for Unique Tree Construction

Construct Binary Tree from Preorder and Inorder Traversal

Construct Binary Tree from Inorder and Postorder Traversal

Flatten Binary Tree to Linked List

Children Sum in a Binary Tree

Time to Burn Entire Tree from a Node

Serialize and Deserialize Binary Tree

BST Fundamentals & Properties

Search in a Binary Search Tree

Minimum & Maximum in a BST

Two Sum IV - Input is a BST

Insert into a Binary Search Tree

Delete Node in a BST

Kth Smallest Element in a BST

Validate Binary Search Tree

Lowest Common Ancestor of a Binary Search Tree

Construct Binary Search Tree from Preorder Traversal

Inorder Successor in BST

Binary Search Tree Iterator

Recover Binary Search Tree

Largest BST Subtree

Graph Types & Terminology

Graph Representation (C++)

Graph Representation (Java)

Number of Connected Components in an Undirected Graph

Breadth-First Search

Depth-First Search

Number of Provinces

Connected Components in Grid

Rotting Oranges

Surrounded Regions

Number of Enclaves

Is Graph Bipartite?

Course Schedule II

Detect Cycle in Undirected Graph

Number of Distinct Islands II

Course Schedule

Course Schedule II

Find Eventual Safe States

Topological Sort

Kahn's Algorithm (BFS Topo Sort)

Detect Cycle in Directed Graph

Alien Dictionary

Shortest Path in Binary Matrix

Path With Minimum Effort

Cheapest Flights Within K Stops

Network Delay Time

Number of Ways to Arrive at Destination

Find the City With the Smallest Number of Neighbors at a Threshold Distance

Shortest Path in Unweighted Graph

Shortest Path in DAG

Dijkstra's Algorithm

Dijkstra: Queue vs Priority Queue

Minimum Steps via Multiply & Mod

Bellman-Ford Algorithm

Floyd-Warshall Algorithm

Number of Operations to Make Network Connected

Most Stones Removed with Same Row or Column

Minimum Spanning Tree Concepts

Prim's Algorithm

Disjoint Set (Union-Find)

Kruskal's Algorithm

Number of Islands II

Making a Large Island

Swim in Rising Water

Critical Connections in a Network

Articulation Points (Cut Vertices)

Kosaraju's Algorithm (Strongly Connected Components)

Introduction to Dynamic Programming

Climbing Stairs

Frog Jump with Variable Steps

House Robber II

Activity Selection

Unique Paths II

Minimum Path Sum

Minimum Falling Path Sum

Ninja and his friends

Partition Equal Subset Sum

Subset Sum Equal to Target

Partition Array Into Two Arrays to Minimize Sum Difference

Count Subset With Target Sum

Count Partitions with Target Difference

Unbounded Knapsack Problem(Repetition of items allowed)

Longest Common Subsequence

Longest Palindromic Subsequence

Delete Operation for Two Strings

Longest Common Subsequence

Longest Common Substring

Minimum Insertion Steps to Make a String Palindrome

Shortest Common Supersequence

Distinct Subsequences

Wildcard Matching

Best Time to Buy and Sell Stock

Best Time to Buy and Sell Stock II

Best Time to Buy and Sell Stock with Cooldown

Best Time to Buy and Sell Stock with Transaction Fee

Best Time to Buy and Sell Stock III

Best Time to Buy and Sell Stock IV

Longest Increasing Subsequence

Print the Longest Increasing Subsequence

Largest Divisible Subset

Longest String Chain

Longest Bitonic Subsequence

Number of Longest Increasing Subsequence

Partition Array for Maximum Sum

Matrix Chain Multiplication

Matrix Chain Multiplication Bottom-Up Approach

Minimum Cost to Cut a Stick

Evaluate Boolean Expression

Palindrome Partitioning II

Count Square Submatrices with All Ones

Maximal Rectangle

Implement Trie (Prefix Tree)

Complete String (All Prefixes Exist)

Count Distinct Substrings via Trie

Maximum XOR of Two Numbers in an Array

Enhanced Trie with Count

Bitwise Foundations for Tries

Maximum XOR With an Element From Array

Minimum Add to Make Parentheses Valid

Polynomial Rolling Hash

Repeated String Match

KMP / Rabin-Karp String Search

Shortest Palindrome

Longest Happy Prefix

Count Palindromic Subsequences

Number of Connected Components in an Undirected Graph

Number of Connected Components in an Undirected Graph on CodePeet.

Loading...

Loading content...