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

肯定是要遍历才能知道出现的次数的。

class Solution {
    public int firstUniqChar(String s) {
        int[] count = new int [26];
        int pos =0;
        for(int i = 0 ;i<s.length();i++)
        {
            count[(int)(s.charAt(i)-'a')]++;
        }
        for(int i = 0 ;i<s.length();i++)
        {
            if(count[(int)(s.charAt(i)-'a')]==1)
            {
                return i;//find
            }
        }
        return -1 ;//miss
    }
}