题解 | #第一个只出现一次的字符#

public class Solution {
    public int FirstNotRepeatingChar(String str) {
        if(str == null || str.length() == 0){
            return -1;
        }

        int[] pos = new int['z' - 'A' + 1];
        int[] cnt = new int['z' - 'A' + 1];

        for(int i = 0; i < str.length(); ++i){
            char c = str.charAt(i);
            pos[c - 'A'] = i;
            cnt[c - 'A']++;
        }

        int index = 0;
        while(index <= str.length() - 1){
            if(cnt[str.charAt(index) - 'A'] == 1){
                return pos[str.charAt(index) - 'A'];
            }
            index++;
        }
        return -1;
    }
}