First Position Unique Character

Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1.

您在真实的面试中是否遇到过这个题？ 

Yes

样例

Given s = "lintcode", return 0.

Given s = "lovelintcode", return 2.

public int firstUniqChar(String s) {        int[] map = new int[200];        for (int i = 0; i < s.length(); i++) {            char c = s.charAt(i);            map[c]++;        }        for (int i = 0; i < s.length(); i++) {            char c = s.charAt(i);            if (map[c] == 1) return i;        }        return -1;    }