Number of distinct elements in a given range
This is a problem in which we have an integer array which contains some elements and our job is to find out number of distinct elements in a given range. We have solved this using three methods with the most efficient approach being a hashing technique with linear time complexity O(N).
Minimum number of characters to be deleted to make string a palindrome
In this problem, we have to formulate an algorithm to find the minimum number of characters to be deleted to make the string a palindrome. This can be solved using the Dynamic Programming approach for longest palindromic subsequence in O(N^2) time.
Minimum characters added to the front of string to make it palindrome
In this problem, we have to formulate an algorithm to find the minimum number of characters to be added to the front of a string to make it a palindrome. To solve this efficiently in linear time O(N), we have to use longest prefix suffix of Knuth Morris Pratt pattern matching algorithm.