public static void main(String args[]) {
        HIndex hi = new HIndex();
        int[] input = {0, 1, 1, 1, 1, 6, 7 ,8};
        System.out.print(hi.hIndex(input));
    }
Given an array of citations (each citation is a non-negative integer) of a researcher,
write a function to compute the researcher's h-index.
https://leetcode.com/problems/h-index/
src/com/interview/array/HIndex.java