# Status Problem video Level Completes Likes 35 Adding Two Numbers with Linked Lists Medium % 0 34 Add two numbers represented by a linked list, Numbers are Stored in REVERSE order Medium % 0 31 Reverse a Linked List Using Recursion Medium % 0 30 Swap Every Kth Node in a LinkedList Medium % 0 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 26 Check if one string is Rotation of another string Beginner % 1 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 12 Efficient Methods to Find Pairs with Sum K in an Array Beginner % 0 11 Check If String has All Unique Characters Beginner % 0 9 Valid or Well Formed Parentheses | Part - 1 Medium % 0 8 Efficient Search in 2D Sorted Array: Find an Element Medium % 0 Adding Two Numbers with Linked Lists Add two numbers represented by a linked list, Numbers are Stored in REVERSE order Reverse a Linked List Using Recursion Swap Every Kth Node in a LinkedList 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 Check if one string is Rotation of another string 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 Efficient Methods to Find Pairs with Sum K in an Array Check If String has All Unique Characters Valid or Well Formed Parentheses | Part - 1 Efficient Search in 2D Sorted Array: Find an Element 1 2 3 4 5 6 7