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King coder
King coder

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500+ Dsa Questions (Easy to Advanced)

๐Ÿ“Œ 1. Arrays (Easy โ†’ Hard)

๐ŸŸข Easy (Available on LeetCode / GFG / HackerRank / InterviewBit)

  • Second Largest Element (GFG)
  • Third Largest Element (GFG)
  • Max Consecutive Ones (LeetCode / GFG)
  • Reverse Array in Groups (GFG)
  • Wave Array (GFG)
  • Repetitive Addition of Digits (GFG)
  • Remove All Occurrences of Element (GFG)
  • Alternate Positive Negative (GFG)
  • Array Leaders (GFG)
  • Missing & Repeating Number (GFG)
  • Missing Ranges of Numbers (GFG)
  • Plus One (LeetCode / GFG)
  • Remove Duplicates from Sorted Array (LeetCode / GFG)
  • Two Sum (LeetCode / InterviewBit)
  • Move Zeros to End (LeetCode / GFG)
  • Rotate Array (LeetCode / InterviewBit)
  • Maximum Consecutive Ones (LeetCode / GFG)
  • Intersection of Two Arrays (LeetCode)
  • Remove Element (LeetCode)

๐ŸŸก Medium & Hard

(Same as previous; journeys from Merge Intervals, Trapping Rain Water, etc.)


2. Strings (Easy โ†’ Hard)

๐ŸŸข Easy (LeetCode / GFG / HackerRank)

  • Anagram Check (GFG / LeetCode)
  • Valid Parentheses (LeetCode)
  • Reverse Words in a String (LeetCode)
  • Longest Common Prefix (LeetCode)
  • String Compression (LeetCode)
  • Count and Say (LeetCode)
  • Valid Palindrome (LeetCode)
  • First Unique Character (LeetCode)
  • Implement strStr() (Needle in a Haystack) (LeetCode)
  • Reverse String (LeetCode)

3. Linked Lists (Easy โ†’ Hard)

๐ŸŸข Easy (LeetCode / GFG / InterviewBit)

  • Reverse a Linked List (LeetCode)
  • Detect Cycle (LeetCode)
  • Merge Two Sorted Lists (LeetCode)
  • Find Middle of Linked List (LeetCode)
  • Delete Node Without Head Pointer (GFG)
  • Remove Linked List Elements (LeetCode)
  • Linked List Cycle II (LeetCode)
  • Delete Node in a Linked List (LeetCode)
  • Merge Two Sorted Linked Lists (InterviewBit/LeetCode)

4. Stacks & Queues (Easy โ†’ Hard)

๐ŸŸข Easy (LeetCode / GFG)

  • Valid Parentheses
  • Min Stack
  • Stack using Queues
  • Queue using Stacks
  • Evaluate Reverse Polish Notation (LeetCode / GFG)
  • Circular Queue Implementation (GFG)

5. Trees (Easy โ†’ Hard)

๐ŸŸข Easy (LeetCode / GFG)

  • Inorder, Preorder, Postorder Traversal (LeetCode)
  • Level Order Traversal (LeetCode)
  • Balanced Binary Tree (LeetCode)
  • Left/Right View of Tree (GFG)
  • Maximum & Minimum Depth of Binary Tree (LeetCode)

6. Graphs (Easy โ†’ Hard)

๐ŸŸข Easy (LeetCode / GFG)

  • BFS & DFS Traversal (LeetCode)
  • Number of Islands (LeetCode)
  • Flood Fill (LeetCode)
  • Clone Graph (LeetCode)
  • Graph Valid Tree (LeetCode)
  • Find if Path Exists in Graph (LeetCode)

7. Recursion & Backtracking (Easy โ†’ Hard)

๐ŸŸข Easy (LeetCode / GFG)

  • Fibonacci (Recursion)
  • Subsets (LeetCode)
  • Permutations (LeetCode)
  • Rat in a Maze (GFG)
  • Power Set (GFG / LeetCode)
  • Count Ways โ€“ small n Coin Change (LeetCode / GFG)

8. Searching & Sorting (Easy โ†’ Hard)

๐ŸŸข Easy (LeetCode / GFG)

  • Binary Search (LeetCode)
  • Insertion, Bubble, Selection Sort (GFG)
  • Sort Array (LeetCode)
  • Square Root Calculation (GFG / LeetCode)

9. Dynamic Programming (Easy โ†’ Hard)

๐ŸŸข Easy (LeetCode / GFG)

  • Min Cost Climbing Stairs (LeetCode)
  • House Robber (LeetCode)
  • Decode Ways (LeetCode)
  • Unique Paths (LeetCode)
  • Climbing Stairs (LeetCode)
  • Maximum Subarray (Kadane) (LeetCode)
  • Best Time to Buy and Sell Stock (LeetCode)

10. Bit Manipulation (Easy โ†’ Hard)

๐ŸŸข Easy (LeetCode / GFG)

  • Single Number (LeetCode)
  • Power of Two (LeetCode)
  • Count Set Bits / Hamming Weight (LeetCode / GFG)
  • XOR of All Elements (Common Practice)
  • Is Power of Two (LeetCode)
  • Hamming Distance (LeetCode)

Common Platforms for Practice

You can find these problems on:

  • GeeksforGeeks โ€” comprehensive tutorials and interview topics
  • LeetCode โ€” curated problems and mock interview environment
  • HackerRank โ€” multi-language challenges and certifications
  • Codeforces, CodeChef โ€” competitive programming contests and practice
  • InterviewBit โ€” structured interview prep path
  • SPOJ, TopCoder, AtCoder, HackerEarth, Exercism, Edabit โ€” varied problem styles

Happy Coding! ๐Ÿš€

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