Implement a stack and a queue with insertion / deletion in O(1). It should expand / shrink in O(n) Given a sorted list with pivot find x. Check if array has duplicate in O(1) space complexity. The array has elements between 0, n-1 and the size of the array is n. Given a string compute the length of the largest sub string having at most k unique characters Kth largest number (large data) Count occurrence of an item in sorted list Sentence Screen Fitting Given a stream of characters and a keyword. Print the keyword if it matches. Shortest path in the grid from bike to person Print duplicates in array Paint n fence with k colors, two adjacent fence should not have the same color. Convert string into reverse Polish notation Convert aabbbaaa into 2a3b3a and vice versa First occurrence of given item in a sorted list Given a non negative integer and a non decreasing array, find the first element which is not smaller than the given number Given a sorted array find the number of occurrences of the target Leetcode: Fruit into basket