# Status Problem video Level Completes Likes 215 Find duplicates in an given array in O(n) time and O(1) space Medium % 0 214 Find the last non repeating character in a given string. Beginner % 0 213 Find the last repeating character in a given string Beginner % 0 212 Find the first non repeating character in a given string Beginner % 0 211 Find the first repeating character in a given string Beginner % 0 209 Find longest Snake sequence in a given matrix Medium % 1 208 Dynamic Programming - Count all paths in 2D Matrix with Obstructions in it Medium % 1 207 Dynamic Programming - Count all paths from top left to bottom right of a mXn matrix Medium % 1 205 Print All Diagonals of a given matrix Medium % 1 204 Dynamic Programming - Edit Distance Problem Hard % 2 202 Dynamic Programming - Box Stacking Problem Hard % 0 200 Dynamic Programming - Highway Billboard Problem Hard % 0 199 Dynamic Programming - Maximum Subarray Problem Medium % 0 198 Kadane's Algorithm - Maximum Subarray Problem Medium % 1 197 Convert Binary Tree into Threaded Binary Tree Hard % 0 196 Double Threaded Binary Tree Complete Implementation Hard % 0 195 Single Threaded Binary Tree Complete Implementation Hard % 0 194 Introduction to Threaded Binary Tree Medium % 0 190 Swap Nodes in pairs in a Linked List by changing links Medium % 0 189 Convert BST to Greater Sum Tree Medium % 0 Find duplicates in an given array in O(n) time and O(1) space Find the last non repeating character in a given string. Find the last repeating character in a given string Find the first non repeating character in a given string Find the first repeating character in a given string Find longest Snake sequence in a given matrix Dynamic Programming - Count all paths in 2D Matrix with Obstructions in it Dynamic Programming - Count all paths from top left to bottom right of a mXn matrix Print All Diagonals of a given matrix Dynamic Programming - Edit Distance Problem Dynamic Programming - Box Stacking Problem Dynamic Programming - Highway Billboard Problem Dynamic Programming - Maximum Subarray Problem Kadane's Algorithm - Maximum Subarray Problem Convert Binary Tree into Threaded Binary Tree Double Threaded Binary Tree Complete Implementation Single Threaded Binary Tree Complete Implementation Introduction to Threaded Binary Tree Swap Nodes in pairs in a Linked List by changing links Convert BST to Greater Sum Tree 1 2 3 4 5 6 7 8 9 10 11 12