src/main/java/com/fishercoder/solutions/_387.java

package com.fishercoder.solutions;

public class _387 {
    public static class Solution1 {
        public static int firstUniqChar(String s) {
            int[] freq = new int[26];
            for (int i = 0; i < s.length(); i++) {
                freq[s.charAt(i) - 'a']++;
            }
            for (int i = 0; i < s.length(); i++) {
                if (freq[s.charAt(i) - 'a'] == 1) {
                    return i;
                }
            }
            return -1;
        }
    }
}