*problem statement*

You are given n numbers from series 0, 1, 2 ... n. Your task is to find the missing number from the series using **O(1) space and O(n) time complexity.**

E.g given a sequence [0, 1, 3]

...Problem that got Max Howell (creator of famous Homebrew ,package management software that is used by 90% of Googlers) rejected in Google's interview.

I guess the problem is worth a try then, lets find out how hard is it..

**Problem Statement**

Often we might come up with a task where we are asked to find not the largest number but 2nd largest or 5th largest or kth largest number from an unsorted array. In such a case, a trivial solution which pops into mind is that, just sort the array and return the element corresponding the kth index...