#DSA — ByteDepth

5 approaches incl. Recursion (Include/Exclude), Recursion (Include/Exclude),…, Backtracking (start-index st…, and more. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA LeetCode Practice 🏢 Amazon

DSA

Permutations

4 approaches incl. Backtracking with a `used` a…, Backtracking via in-place sw…, Iterative (insert into every…, and more. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA LeetCode Practice 🏢 Amazon

DSA

Permutation in String

Sliding Window - Fixed approach. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA LeetCode Practice

DSA

Rat in a Maze

Recursion & Backtracking. Time O(4^(m*n), Space O(m*n).

Medium·Aug 8, 2026

DSA Backtracking Recursion

DSA

M Coloring Problem

Backtracking approach. Optimal — Time O(m^n), Space O(n).

Medium·Aug 8, 2026

DSA Backtracking Recursion

DSA

Find All Anagrams in a String

Sliding Window - Fixed approach. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA LeetCode Practice

DSA

N Queens

Covers: Rules, Approach - Backtracking, Improved - hashsets. Optimal — Time O(N!), Space O(N2).

Hard·Aug 8, 2026

DSA Backtracking Recursion

DSA

Permutations of a String

Recursion & Backtracking. Time O(n! * n), Space O(n! * n).

Medium·Aug 8, 2026

DSA Backtracking Recursion

DSA

Palindrome partitioning

Recursion & Backtracking. Time O(n * 2^n), Space O(n).

Medium·Aug 8, 2026

DSA Backtracking Recursion

DSA

Combination Sum II

Recursion & Backtracking. Time O(2n), Space O(n).

Medium·Aug 8, 2026

DSA Backtracking Recursion

DSA

Combination Sum

Covers: Brute Force - Recursion, When to Use Tabulation. Optimal — Time O(2T), Space O(T).

Medium·Aug 8, 2026

DSA Backtracking Recursion

DSA

Subset II

Recursion & Backtracking. Time O(2^n), Space O(n * 2^n).

Medium·Aug 8, 2026

DSA Backtracking Recursion

DSA

Spiral Matrix

Simulation approach.

Medium·Aug 8, 2026

DSA LeetCode Practice

DSA

Set Matrix Zeros

Covers: Set, Greedy. Optimal — Time O(m*n), Space O(1).

Medium·Aug 8, 2026

DSA LeetCode Practice

DSA

Merge Two Sorted Arrays

Covers: Extra Space (Naive), Two Pointers from End (Optim…, Gap Method (Shell Sort idea). Optimal — Space O(m + n).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Largest Subarray with Sum 0

Covers: Brute Force, Optimal. Optimal — Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Linear Search

Arrays. Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Longest Consecutive Sequence in an Array

Covers: Brute Force, Better, Optimal. Optimal — Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Arrays LeetCode 🏢 Amazon

DSA

Longest subarray with sum K

Covers: Brute Force, Optimal (Only Positives), Optimal Approach (Handling P…. Optimal — Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Optimal Approach: Boyer-Moore Voting Algorithm

Boyer-Moore Voting Algorithm approach. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Set Matrix Zeroes

Covers: Brute Force, Optimal. Optimal — Time O(m*n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Maximum Consecutive Ones

Optimal approach. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Maximum Subarray

Covers: Brute Force, Kadane's Algo. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Merge two sorted arrays without extra space

Optimal approach. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Largest Element

Covers: Sorting, Linear Scan. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Minimum Size Subarray Sum

Covers: Brute Force, Sliding Window. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Missing Number

5 approaches incl. Brute Force, Better, II, and more. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Move Element to end

Arrays problem — solution with code and analysis.

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Move Zeros to End

Covers: Brute Force, Two pointer. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Next Permutation

Covers: Brute Force, Optimal. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026·7 min read

DSA Arrays LeetCode 🏢 Amazon

DSA

Count Inversions

Covers: Brute Force, Merge Sort (Optimal).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Pascal's Triangle — Part I

nCr Formula approach. Optimal — Time O(c), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Leaders in an Array

optimal approach. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Search in 2D matrix

Covers: Brute Force, Better, Optimal. Optimal — Time O(log(n * m), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Majority Element (n/2 times)

Covers: Brute Force, Better, Optimal. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Reverse pairs

Covers: Brute Force, Better.

Hard·Aug 8, 2026

DSA Arrays LeetCode

DSA

2 Sum

Covers: HashMap, Optimal. Optimal — Time O(nlogn), Space O(n).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

4 Sum

Covers: Brute Force, Better, Optimal. Optimal — Time O(nlogn), Space O(t).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Longest Consecutive Sequence

Covers: sorting Based, Better, Union Find. Optimal — Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Largest subarray with 0 sum

Arrays. Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Count Number of Subarrays with Given Xor

Covers: Brute Force, Optimal. Optimal — Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Product of Array Except Self

Covers: Brute Force, prefix Sum, Prefix Sum - Space Optimizat…. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode 🏢 Amazon

DSA

Best time to buy and sell stock

Covers: Brute Force, Optimal. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Check if array is sorted

Arrays. Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Container With Most Water

Covers: brute Force, Two pointer. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode 🏢 Amazon

DSA

Contains Duplicate

Covers: Brute Force, Sorting, HashSet. Optimal — Time O(n), Space O(n).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Count subarrays with given sum

Covers: Brute Force, Optimal, Working. Optimal — Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Count subarrays with given xor K

Covers: Brute Force, Better. Optimal — Time O(n^2), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Find Minimum in Rotated Sorted Array

Covers: Brute Force, Binary Search. Optimal — Time O(log n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode 🏢 Amazon 🏢 Google

DSA

Maximum Subarray Sum

Covers: Brute Force, Optimal. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode 🏢 Amazon

DSA

Design Add and Search Words Data Structure

Trie. Space O(m).

Medium·Aug 8, 2026

DSA LeetCode Practice

DSA

Counting Bits

Covers: brute Force, Dynamic Programming. Optimal — Time O(n), Space O(n).

Easy·Aug 8, 2026

DSA Bit Manipulation LeetCode

DSA

Reverse Bits

Covers: Brute Force, Bit Manipulation. Optimal — Time O(1), Space O(1).

Easy·Aug 8, 2026

DSA Bit Manipulation LeetCode

DSA

Sum of Two Integers

Bit Manipulation. Time O(1), Space O(1).

Medium·Aug 8, 2026

DSA Bit Manipulation LeetCode

DSA

Single Element in a Sorted Array

Covers: Brute Force - XOR, Better - Binary Search. Optimal — Time O(logn), Space O(1).

Medium·Aug 8, 2026

DSA Binary Search LeetCode 🏢 Amazon

DSA

Median of 2 sorted Arrays

Covers: Naive, Two Pointer. Optimal — Time O(n+m), Space O(1).

Hard·Aug 8, 2026

DSA Binary Search LeetCode 🏢 Google 🏢 Amazon 🏢 Microsoft 🏢 Meta 🏢 Apple

DSA

K-th element of two Arrays

Covers: Naive, Two Pointer. Optimal — Time O(n+m), Space O(1).

Medium·Aug 8, 2026

DSA Binary Search LeetCode

DSA

Allocate Books

Covers: Linear Search, Binary Search. Optimal — Time O(n*logn), Space O(1).

Medium·Aug 8, 2026

DSA Binary Search LeetCode

DSA

Palindrome Pairs

Trie. Time O(n² * k), Space O(n²).

Hard·Aug 8, 2026

DSA Trie LeetCode

DSA

Longest Word in Dictionary

Covers: Set, Trie Based. Optimal — Time O(26*L), Space O(nL).

Medium·Aug 8, 2026

DSA Trie LeetCode

DSA

Number of 1 Bits

Covers: Shift Right and Count, Brian Kernighan's Algo. Optimal — Time O(t), Space O(1).

Easy·Aug 8, 2026

DSA Bit Manipulation LeetCode

DSA

Power Set

Covers: Brute Force, Trie. Optimal — Time O(N^2), Space O(n).

Easy·Aug 8, 2026

DSA Trie LeetCode

DSA

Count Distinct Substrings

Using Trie approach. Optimal — Time O(n^2), Space O(n^2).

Medium·Aug 8, 2026

DSA Trie LeetCode

DSA

Complete String

Trie. Time O(nL), Space O(nL).

Medium·Aug 8, 2026

DSA Trie LeetCode

DSA

Implement Trie - II

Trie problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Trie LeetCode

DSA

Implement Trie

Trie problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Trie LeetCode

DSA

Binary Search

Binary Search. Time O(logn), Space O(1).

Easy·Aug 8, 2026

DSA Binary Search LeetCode

DSA

Valid Anagrams

Covers: Brute Force: Sorting, Hash Map, For fixed characters. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Strings LeetCode

DSA

Palindromic Substring

Covers: Brute Force: generate all su…, Expansion on center, DP. Optimal — Time O(n2), Space O(n2).

Medium·Aug 8, 2026

DSA Strings LeetCode

DSA

Smallest Difference

Arrays. Time O(nlogn + mlogm), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Range Sum Query

Prefix Sum approach.

Easy·Aug 8, 2026

DSA LeetCode Practice

DSA

Remove duplicates from sorted array

Covers: Brute Force, Two Pointer. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Left Rotate Array by K Places

Covers: Brute Force, Segment Reversal. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Left Rotate Array by One

Arrays. Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Rotate matrix by 90 degrees

Covers: Brute Force, optimal. Optimal — Time O(m*n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Search in Rotated Sorted Array

Covers: Brute Force: Linear Search, Binary Search. Optimal — Time O(log n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode 🏢 Amazon 🏢 Google

DSA

Second Largest

Covers: Brute Force, Better, Optimal. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Single number

Covers: Brute Force: hashmap, XOR. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Minimum Window Substring

Covers: Brute Force, Sliding Window. Optimal — Time O(n), Space O(1).

Hard·Aug 8, 2026

DSA Strings LeetCode

DSA

Sort an array of 0's 1's and 2's

Covers: Brute Force: Sorting, Store freq of 0s, 1s and 2s, Dutch National Flag Algo. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Sorted Squared Array

Covers: Brute Force, Optimal. Optimal — Time O(n), Space O(n).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Subarray Sum Equals K

Covers: Brute Force, Prefix Sum, Optimal Single-Pass. Best — Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Tournament Winner

Arrays. Time O(n), Space O(n).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Transpose Matrix

Arrays. Time O(h × w), Space O(h × w).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Two Sum

Covers: Brute Force, Better, Optimal. Optimal — Time O(n), Space O(n).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Union of two sorted arrays

Covers: Brute Force: hashset, Optimal. Optimal — Time O(n + m), Space O(n + m).

Medium·Aug 8, 2026

DSA Arrays LeetCode

DSA

Validate Subsequence

Covers: Brute Force, Better. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Arrays LeetCode

DSA

Best Time to Buy and Sell Stock - II

Covers: Recursive, Memoized, Tabulation. Optimal — Time O(2n), Space O(1).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Coin Change

Covers: Memoized Version, Tabulation: 2-D, DP Approach 1D. Optimal — Time O(n*A), Space O(A).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Coin Change II

Covers: Recursive Version, Memoized Version, Tabulation:. Optimal — Time O(n*A), Space O(n*A).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Climbing Stairs

4 approaches incl. A. Recursive, B. Memoized, B. Tabulation, and more. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Cherry Pickup - II

DP approach. Optimal — Time O(R*C*C), Space O(R*C*C).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Cherry Pickup - I

DP approach. Optimal — Time O(n^4), Space O(n^4).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Best Time to Buy and Sell Stock with transaction fee - VI

Covers: Recursive, Memoized, Tabulation. Optimal — Time O(2n), Space O(1).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Best Time to Buy and Sell Stock with Cooldown - V

Covers: Recursive, Memoized, Tabulation. Optimal — Time O(2n), Space O(1).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Best Time to Buy and Sell Stock - IV

Covers: Recursive, Memoized. Optimal — Time O(kn), Space O(2 * k).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Best Time to Buy and Sell Stock - III

Covers: Recursive, Memoized. Optimal — Time O(n), Space O(2 * 3).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Count Square Submatrices with All Ones

Covers: Brute Force, Optimal. Optimal — Time O(m * n), Space O(m * n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Best Time to Buy and Sell Stock

Covers: Naive, Better. Optimal — Time O(n), Space O(1).

Easy·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Burst Balloons

Covers: Recursive, Memoized.

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Egg Dropping Problem

Covers: Recursive, Memoized, Binary Search. Optimal — Time O(e x f x logf), Space O(e x f).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Partition Equal Subset Sum

Tabulation approach. Optimal — Time O(n*k), Space O(k).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Minimum Path Sum

4 approaches incl. Recursive, Memoized Version, Tabulation: Space Optimized, and more. Optimal — Time O(m*n), Space O(m*n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Matrix Chain Multiplication

Covers: Recursive, Memoized. Optimal — Time O(n), Space O(n).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

0-1 Knapsack

Covers: Recursive, Memoized, Follow up - Return the indic…. Optimal — Time O(n), Space O(n*w).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Longest Common Subsequence

5 approaches incl. Brute Force, Recursive, Memoized DP, and more. Optimal — Time O(m×n), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Longest Increasing Subsequence

4 approaches incl. Brute Force, Memoized, DP, and more. Optimal — Time O(n*log n), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

House Robber - II

Covers: Recursive, Memoized version, Tabulation version. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Dynamic Programming DP 🏢 Amazon

DSA

Minimum Falling Path Sum

Covers: Recursive, Memoized. Optimal — Time O(m*n), Space O(m*n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Minimum Cost to cut the stick

Covers: Recursive, Tabulation. Optimal — Time O(n^2), Space O(n^2).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Maximum Sum Increasing Subsequence

Covers: DP, Binary Search. Optimal — Time O(n*log n), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Maximal Square

Covers: Brute Force, Better, Building subproblem. Optimal — Time O(m*n), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Maximal Rectangle

Dynamic Programming. Time O(m * n), Space O(n).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Maximum Length of Bitonic Subsequence

DP approach.

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Longest Palindromic Subsequence

Covers: Recursion, Memoized DP. Optimal — Time O(n^2), Space O(n^2).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Longest common substring

Dynamic Programming. Time O(m*n), Space O(m*n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

House Robber - III

Covers: Recursive, Memoized version. Optimal — Time O(logn), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

MAXIMUM PRODUCT SUBARRAY

Covers: Brute Force, Prefix & Suffix Product Trav…, DP. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

House Robber

4 approaches incl. Recursive, Memoized version, Tabulation version, and more. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Frog Jump

4 approaches incl. A. Recursive, B. Recursive, B. Tabulation, and more. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Frog Jump with k distances

Covers: Recursive, Memoized Version, Tabulation version. Optimal — Time O(k*n), Space O(k).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Super Egg Drop

Covers: Memoized, Binary Search. Optimal — Time O(e x f x logf), Space O(e x f).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Edit Distance

Covers: Recursive, DP. Optimal — Time O(m*n), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Delete Operation for Two Strings

4 approaches incl. Brute Force, Recursive, Memoized DP, and more. Optimal — Time O(m*n), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Decode Ways

Covers: Brute Force: Recursion + Bac…, DP Solution: Tabulation, DP Solution: Tabulation - Sp…. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Subsets with sum k

Covers: Recursive, Memoized. Optimal — Time O(n*k), Space O(n*k).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Convert Sorted Array to Binary Search Tree

Divide and Conquer (Pick Mid… approach. Optimal — Time O(n), Space O(log n).

Easy·Aug 8, 2026

DSA LeetCode Practice

DSA

Kth Largest in unsorted Array

Covers: Naive, Use Min Heap. Optimal — Time O(nlogk), Space O(1).

Medium·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Distinct Numbers in Window

Covers: Brute Force - Set, Sliding Window + unordered M…, Other Optimization. Optimal — Time O(N), Space O(N).

Medium·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Kth Largest Element in a Stream

Brute Force -> Sorting + Set approach. Optimal — Time O(nlogn), Space O(k).

Easy·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Find Median in Data Stream

4 approaches incl. Naive, Two Heaps, 1. How Do We Maintain the Me…, and more. Optimal — Time O(logn), Space O(n).

Hard·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Flatten Binary Tree to Linked List

Covers: RECURSION, USING STACK, MORRIS MODIFIED.

Medium·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Validate Binary Search Tree

Covers: Inorder Traversal (Strictly…, Iterative Inorder (Stack). Optimal — Time O(n), Space O(h).

Medium·Aug 8, 2026

DSA Binary Search Tree BST 🏢 Amazon

DSA

Lowest Common Ancestor of a Binary Search Tree

Optimal approach.

Medium·Aug 8, 2026

DSA Binary Search Tree BST

DSA

Kth Smallest Element in a BST

Covers: Brute Force, Better, Optimal. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Binary Search Tree BST

DSA

Delete Node in a BST

Recursive BST Deletion (Inor… approach. Optimal — Time O(h), Space O(h).

Medium·Aug 8, 2026

DSA LeetCode Practice 🏢 Amazon

DSA

All Nodes Distance K in Binary Tree

Binary Trees. Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Binary Tree LeetCode 🏢 Amazon

DSA

Ceil in BST

BST. Space O(1).

Easy·Aug 8, 2026

DSA Binary Search Tree BST

DSA

Floor in BST

BST. Space O(1).

Easy·Aug 8, 2026

DSA Binary Search Tree BST

DSA

Upper bound

Binary Search. Time O(logn), Space O(1).

Easy·Aug 8, 2026

DSA Binary Search LeetCode

DSA

Search Insert Position

Covers: Brute Force, Binary Search. Optimal — Time O(log n), Space O(1).

Easy·Aug 8, 2026

DSA Binary Search LeetCode 🏢 Google

DSA

Search in Rotated Sorted Array - II

Binary Search. Time O(logn), Space O(1).

Medium·Aug 8, 2026

DSA Binary Search LeetCode

DSA

Find Peak Element

Binary Search. Time O(logn), Space O(1).

Medium·Aug 8, 2026

DSA Binary Search LeetCode

DSA

Number of occurrences in Sorted Array

Binary Search. Time O(logn), Space O(1).

Easy·Aug 8, 2026

DSA Binary Search LeetCode

DSA

Implement Lower Bound

Binary Search. Time O(logn), Space O(1).

Easy·Aug 8, 2026

DSA Binary Search LeetCode

DSA

Koko Eating Bananas

Covers: Brute Force, binary Search. Optimal — Time O(logn), Space O(1).

Medium·Aug 8, 2026

DSA LeetCode Practice 🏢 Amazon 🏢 Google

DSA

Binary Tree Zigzag Level Order Traversal

Binary Trees. Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

LRU Cache

Design. Time O(1).

Medium·Aug 8, 2026

DSA Design LeetCode 🏢 Amazon

DSA

Design Twitter

Covers: LinkedList + Hashmap, 📌 `getNewsFeed(int userId)`.

Medium·Aug 8, 2026

DSA Design LeetCode

DSA

Serialize and Deserialize Binary Tree

Binary Trees problem — solution with code and analysis.

Hard·Aug 8, 2026

DSA Binary Tree LeetCode 🏢 Amazon

DSA

Same tree

Covers: Recursive, Iterative. Optimal — Time O(n), Space O(n).

Easy·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Right Side View of Binary Tree

Covers: BFS (Level Order), DFS (Preorder, Right-First), DFS (Postorder, Left-First,…. Optimal — Space O(w).

Medium·Aug 8, 2026

DSA LeetCode Practice

DSA

Populate Next Right Pointers in Each Node

Covers: O(1) Space — Level Pointer T…, BFS Level Order. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA LeetCode Practice

DSA

Path Sum II

Covers: DFS + Backtracking (Optimal), DFS with Running Sum (Accumu…, Iterative DFS with Explicit…. Optimal — Space O(n·h).

Medium·Aug 8, 2026

DSA LeetCode Practice 🏢 Amazon

DSA

Binary Tree Maximum Path Sum

Binary Trees. Time O(n), Space O(h).

Hard·Aug 8, 2026

DSA Binary Tree LeetCode 🏢 Amazon

DSA

Binary Tree Level Order Traversal

Binary Trees. Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Missing and Repeating Number

4 approaches incl. Brute Force, Better, Maths, and more. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Intervals Arrays

DSA

Lowest Common Ancestor of a Binary Tree

10 approaches incl. Recursive, Parent Pointers + Hash Set, Path Compression (Path to Ro…, and more. Optimal — Time O(n), Space O(h).

Medium·Aug 8, 2026

DSA Binary Tree LeetCode 🏢 Amazon

DSA

Invert Binary Tree

Covers: Recursion, Iterative. Optimal — Time O(n), Space O(n).

Easy·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Maximum Depth of Binary Tree

Covers: Recursive, Iterative. Optimal — Time O(n), Space O(n).

Easy·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Diameter of Binary Tree

Covers: DFS with Height Tracking (Op…, Naive DFS (Two Separate Func…, DFS with Class-Level Variabl…. Optimal — Time O(n²), Space O(h).

Easy·Aug 8, 2026

DSA LeetCode Practice

DSA

Construct Binary Tree from Inorder and Postorder Traversal

Binary Trees problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Construct Binary Tree from Preorder and Inorder Traversal

Binary Trees problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Subtree of Another Tree

Binary Trees. Time O(n × m), Space O(h).

Easy·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Burning Tree

Binary Trees problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Number of Ways to Arrive at Destination

Graphs. Time O(m log n), Space O(m+n).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Word Search

DFS - Backtracking approach. Optimal — Time O(mn * 4^L), Space O(1).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Word Ladder

Graphs problem — solution with code and analysis.

Hard·Aug 8, 2026

DSA Graphs BFS

DSA

Valid Tree

Graphs problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Surrounded Regions

Graphs. Time O(V^2).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Shortest Path in Binary Matrix

Graphs. Time O(V^2).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Rotten Oranges

Graphs. Time O(V^2).

Medium·Aug 8, 2026

DSA Graphs BFS 🏢 Amazon

DSA

Redundant Connection

Graphs. Time O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Path with Minimum Effort

Graphs. Time O(ElogV).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Pacific Atlantic Water Flow

Covers: To Note, DFS, BFS. Optimal — Time O(m x n), Space O(m x n).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Job Sequencing

Covers: Greedy, optimized Greedy with DSU, Dp. Optimal — Time O(nlogn), Space O(m).

Medium·Aug 8, 2026

DSA Greedy LeetCode

DSA

Number of Provinces

DFS vs BFS approach. Optimal — Time O(V^2), Space O(n).

Medium·Aug 8, 2026

DSA Graphs BFS 🏢 Amazon

DSA

Number of operations to make network connected

Covers: 1. DFS Based, Disjoint Set Based. Optimal — Time O(m * alpha(n), Space O(n).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Connected Components

Covers: DFS, Union Find. Optimal — Time O(V + E), Space O(V).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Network Delay Time

Graphs — single-source shortest path with Dijkstra. Time O(E log V), Space O(V + E).

Medium·Aug 8, 2026

DSA Graphs Dijkstra 🏢 Google

DSA

Flood Fill

Graphs. Time O(mxn), Space O(mxn).

Easy·Aug 8, 2026

DSA Graphs BFS

DSA

Find the city with the smallest number of neighbors in a threshold distance

Covers: Dijkstra's Algo, Floyd warshall's. Optimal — Time O(n^3), Space O(n^2).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Find Eventual Safe States

Graphs. Space O(V).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Evaluate Division

Graphs. Time O(Q × (V + E), Space O(V).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Course Schedule - IV

Using DFS approach. Optimal — Time O(Q *(N+P), Space O(N+P).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Find Median from Data Stream

Covers: Brute Force, Follow Ups. Optimal — Space O(1).

Hard·Aug 8, 2026

DSA Heap Priority Queue

DSA

Non-overlapping Intervals

Covers: Greedy, DP. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Intervals Arrays

DSA

Merge Intervals

Covers: Linear scan, No extra Space. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Intervals Arrays 🏢 Amazon

DSA

Meeting Rooms III

Intervals problem — solution with code and analysis.

Hard·Aug 8, 2026

DSA Intervals Arrays

DSA

Meeting Rooms II

Covers: Sweep line algorithm (or tim…, Min Heap (Priority Queue), Two Sorted Arrays (Two Point…. Optimal — Time O(n log n), Space O(n).

Medium·Aug 8, 2026

DSA Intervals Arrays 🏢 Amazon

DSA

Meeting Rooms

Intervals. Time O(N * logN), Space O(N).

Easy·Aug 8, 2026

DSA Intervals Arrays

DSA

Maximum meetings

Greedy approach. Optimal — Time O(N * logN), Space O(N).

Medium·Aug 8, 2026

DSA Intervals Arrays

DSA

Insert Interval

4 approaches incl. Brute Force: Linear Iteratio…, Better: Binary Search, Alternate Approach: O(nlogn), and more. Optimal — Time O(log n), Space O(1).

Medium·Aug 8, 2026

DSA Intervals Arrays

DSA

Top K Frequent Elements

Summmary approach. Optimal — Time O(n log k), Space O(n).

Medium·Aug 8, 2026

DSA Heap Priority Queue 🏢 Amazon

DSA

Merge K sorted arrays

Covers: Naive, Using Min heap. Optimal — Time O(nlogk), Space O(k).

Hard·Aug 8, 2026

DSA Heap Priority Queue

DSA

Minimum insertions or deletions to convert string A to B

Tabulation approach. Optimal — Time O(m*n), Space O(m*n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Maximum Sum Combination

Covers: Naive, Better, So the intuition is:. Optimal — Time O(n log n + K log K), Space O(K).

Medium·Aug 8, 2026

DSA Heap Priority Queue

DSA

Kth Largest Element in an Array

Covers: Sort (Naive), Max Heap, Min Heap of Size k (Optimal). Optimal — Time O(n log k), Space O(k).

Medium·Aug 8, 2026

DSA Heap Priority Queue 🏢 Amazon

DSA

MinHeap/MaxHeap Implementation

Heaps problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Heap Priority Queue

DSA

Valid Sudoku

Hashing & Sorting problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Hashing Sorting

DSA

Two Sum II - Input Array Is Sorted

Two Pointer approach. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA LeetCode Practice

DSA

Group Anagrams

Covers: Sorting + Hashing, character counts Based key. Optimal — Time O(n * k), Space O(n * k).

Medium·Aug 8, 2026

DSA Hashing Sorting 🏢 Amazon

DSA

Jump Game

Covers: Recursion, Greedy. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Greedy LeetCode

DSA

Jump Game III

Greedy. Time O(n), Space O(n).

Medium·Aug 8, 2026

DSA Greedy LeetCode

DSA

Jump Game II

Covers: Recursive, DP, Greedy. Optimal — Time O(n), Space O(1).

Medium·Aug 8, 2026

DSA Greedy LeetCode 🏢 Amazon

DSA

Unique Paths - II

4 approaches incl. A. Recursive, B. Memoization, B. Tabulation, and more. Optimal — Time O(m * n), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Topological sort - BFS

Graphs. Time O(N), Space O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Detect Cycle in an directed graph - BFS

Graphs. Time O(N), Space O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Detect Cycle in an directed graph - DFS

Graphs. Time O(N), Space O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Detect Cycle in an undirected graph - DFS

Graphs. Time O(N), Space O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Detect Cycle in an undirected graph - BFS

Graphs. Time O(N), Space O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

BFS TRAVERSAL

Graphs. Time O(V+E), Space O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

DFS TRAVERSAL

Graphs. Time O(V+E), Space O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Word Break

5 approaches incl. Naive: Recursive, Memoization, Tabulation, and more. Optimal — Time O(n^2), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Restore IP Addresses

Backtracking approach. Optimal — Time O(27).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Unique Paths

5 approaches incl. A. Recursive, B. Memoization, B. Tabulation, and more. Optimal — Time O(min(m,n), Space O(1).

Medium·Aug 8, 2026

DSA Dynamic Programming DP 🏢 Amazon

DSA

Unique Paths - III

A. DFS approach.

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Course Schedule - I

Covers: DFS, BFS - TOPOLOGICAL. Optimal — Time O(N+E), Space O(N).

Medium·Aug 8, 2026

DSA Graphs BFS 🏢 Amazon 🏢 Google

DSA

Knapsack with Duplicate Items

Memoized Version approach. Optimal — Time O(n x W), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Subset Sum equal to target

Covers: Recursion, Memoized, Tabulation. Optimal — Time O(n*k), Space O(n*k ).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Shortest common super-sequence

Dynamic Programming. Time O(m*n), Space O(m*n).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Russian Doll Envelopes

Covers: Brute Force: O(n²) DP, Solution: O(n log n) Patienc…. Optimal — Time O(n log n), Space O(n).

Hard·Aug 8, 2026

DSA LeetCode Practice

DSA

Rod Cutting

Covers: Memoized, tabulation. Optimal — Time O(n x n), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Print Longest Increasing Subsequence

DP approach. Optimal — Time O(n*n), Space O(n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Print all longest Common subsequence

Dynamic Programming. Time O(m + n).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Number of Longest Increasing Subsequence

Time O(n^2), Space O(n).

Medium·Aug 8, 2026

DSA LeetCode Practice

DSA

Ninja Training

4 approaches incl. A. Recursive, B. Memoization, B. Tabulation, and more. Optimal — Time O(n * 4 * 3), Space O(4).

Medium·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Minimum Insertion Steps to Make a String Palindrome

Covers: Recursion, Memoized DP. Optimal — Time O(n^2), Space O(n).

Hard·Aug 8, 2026

DSA Dynamic Programming DP

DSA

Clone Graph

Graphs problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Alien Dictionary

Graphs problem — solution with code and analysis.

Hard·Aug 8, 2026

DSA Graphs BFS 🏢 Google

DSA

Minimum Spanning Tree: Prim's Algorithm

Graphs. Time O(ElogE), Space O(V^2).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Minimum Spanning Tree: Kruskal's Algorithm

Graphs. Time O(ElogE), Space O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Shortest Path: Floyd Warshall Algorithm

Alogrithm approach. Optimal — Time O(V^3 ), Space O(V^2 ).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

All Paths From Source to Target

Graphs. Time O(2^N * N), Space O(2^N * N).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Shortest Path Algorithm - Bellman Ford algorithm

5 approaches incl. Negative weight cycle:, Why (V-1) times?, Detection of a Negative Weig…, and more. Optimal — Time O(V*E), Space O(V).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Cheapest Flights Within K Stops

Graphs problem — solution with code and analysis.

Medium·Aug 8, 2026

DSA Graphs BFS 🏢 Amazon

DSA

Shortest Path Algorithm - Dijkstra algorithm

Covers: Data structures Used, If path is needed. Optimal — Time O( (E+V), Space O( |V| ).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Strongly Connected Components - Kosaraju's algorithm

The Algorithm approach. Optimal — Time O(V+E), Space O(V+E).

Hard·Aug 8, 2026

DSA Graphs BFS

DSA

Bipartite Graph - DFS

Covers: Sample 1, Sample 2, Observations. Optimal — Time O(N*(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Bipartite Graph - BFS

Covers: Sample 1, Sample 2, Observations. Optimal — Time O(N*(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS

DSA

Course Schedule - II

Using BFS - Kahn's Algo approach. Optimal — Time O(N+P), Space O(N+P).

Medium·Aug 8, 2026

DSA Graphs BFS 🏢 Google

DSA

Number of Islands

Graphs. Time O(V^2).

Medium·Aug 8, 2026

DSA Graphs BFS 🏢 Amazon

DSA

Topological sort - DFS

Graphs. Time O(N), Space O(V+E).

Medium·Aug 8, 2026

DSA Graphs BFS