题解 | #找出字符串中第一个只出现一次的字符#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
 // 注意 while 处理多个 case
            String s1 = in.nextLine();
            //String s2 = in.nextLine();
            //getSevenNum(a);
            //getKnum(s1,s2);
            getOnecChar(s1);
 
    }

    public static void getOnecChar(String str) {
        int[] nums = new int[27];
        char[] chars = str.toCharArray();
        for (int i = 0; i < chars.length; i++) {
            if (nums[chars[i] - 97] == 0) {
                nums[chars[i] - 97] = 1;
            } else {
                nums[chars[i] - 97] += 1;
            }
        }
        char result = '0' ;
        for (int i = 0; i < chars.length; i++) {
            int index = chars[i] - 97;
            if (nums[index] == 1) {
                result = chars[i];
                break;
            }
        }
        if (result == '0') {
            System.out.println(-1);
        } else {
            System.out.println(result);
        }
    }
}