Featured Lists Top 20 Problems on Dynamic programming Top 10 Problems on Backtracking Top 20 Problems on Graph Top 25 Problems on Trees Top 10 Problems on Bits Manipulation Top 15 Problems in LinkedList All Problems # Status Problem video Level Completes Likes 29 Delete a Node in the Middle of a Linked List Without Access to Head Node Beginner % 0 28 Determine the Nth Node from the Tail in a Linked List Beginner % 0 27 Remove Duplicates from an Unsorted Linked list Beginner % 0 26 Check if one string is Rotation of another string Beginner % 1 25 String Compression using count of repeated characters - Run Length Encoding Beginner % 0 24 Replace Spaces with '%20' Without Using Default Functions Medium % 0 23 Find Whether Two Strings are Permutation of each other Beginner % 1 22 Find Intersection Point in Two Linked Lists Medium % 0 21 Linked List cycle detection - Tortoise and Hare Algorithm Medium % 0 20 Reverse a Linked List Beginner % 0 19 Exploring All Paths, Including Diagonal, from Top Left to Bottom Right in 2D Array Medium % 1 18 All Paths from Top Left to Bottom Right in 2D Array Medium % 0 17 Merge or Combine Two Sorted Linked Lists Medium % 0 16 Singly Linked List Implementation Beginner % 0 15 Efficiently Rearrange Positive and Negative Numbers in Array on Each Side Hard % 0 14 Longest Shared Prefix Sequence in a String Medium % 0 13 Print All Elements of Two Dimensional Array in Spiral Order Medium % 0 12 Efficient Methods to Find Pairs with Sum K in an Array Beginner % 0 11 Check If String has All Unique Characters Beginner % 0 10 Quick Sort Implementation Medium % 0 9 Valid or Well Formed Parentheses | Part - 1 Medium % 0 8 Efficient Search in 2D Sorted Array: Find an Element Medium % 0 7 Determine If a String is Palindrome Beginner % 0 6 Find a peak element in a Given Array Beginner % 0 5 Find two Missing Numbers in a Sequence of Consecutive Numbers Beginner % 0 4 Find a Missing Number From a Sequence of Consecutive Numbers Beginner % 0 3 Hash Table - Java Beginner % 0 2 Merge Sort - Updated - Most Efficient ways to Implement Medium % 1 1 Binary Search Beginner % 0 Delete a Node in the Middle of a Linked List Without Access to Head Node Determine the Nth Node from the Tail in a Linked List Remove Duplicates from an Unsorted Linked list Check if one string is Rotation of another string String Compression using count of repeated characters - Run Length Encoding Replace Spaces with '%20' Without Using Default Functions Find Whether Two Strings are Permutation of each other Find Intersection Point in Two Linked Lists Linked List cycle detection - Tortoise and Hare Algorithm Reverse a Linked List Exploring All Paths, Including Diagonal, from Top Left to Bottom Right in 2D Array All Paths from Top Left to Bottom Right in 2D Array Merge or Combine Two Sorted Linked Lists Singly Linked List Implementation Efficiently Rearrange Positive and Negative Numbers in Array on Each Side Longest Shared Prefix Sequence in a String Print All Elements of Two Dimensional Array in Spiral Order Efficient Methods to Find Pairs with Sum K in an Array Check If String has All Unique Characters Quick Sort Implementation Valid or Well Formed Parentheses | Part - 1 Efficient Search in 2D Sorted Array: Find an Element Determine If a String is Palindrome Find a peak element in a Given Array Find two Missing Numbers in a Sequence of Consecutive Numbers Find a Missing Number From a Sequence of Consecutive Numbers Hash Table - Java Merge Sort - Updated - Most Efficient ways to Implement Binary Search 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16