1.Given a string, write a function that return if it is Palindrome. This wasn't asked directly but from interviewer example i was need to understand that this function must ignore all spaces and special symbols. 2. Given an array, write a function that return true if any 3 elements of this array can sum to 0. My first solution was the simplest and far from best which result in O(n^3). Then interviewer asked me to improve to improve it to O(n^2). This give me a hint that i can use Hash to reduce complexity.
