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) {
        test59();
    }
    private static void test59() {
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) {
            String a = in.nextLine();
            char[] c = a.toCharArray();
            String v = "";
            for (int i = 0; i <= a.length() - 1; i++) {

                if (i == 0 && !a.substring(i + 1).contains(String.valueOf(c[i]))) {
                    v = String.valueOf(c[i]);
                    break;
                }
                if (i != 0 && i != a.length() - 1 &&
                        !a.substring(0, i).contains(String.valueOf(c[i]))
                        && !a.substring(i + 1).contains(String.valueOf(c[i]))) {
                    v = String.valueOf(c[i]);
                    break;
                }
                if (i == a.length() - 1 && !a.substring(0, i).contains(String.valueOf(c[i]))) {
                    v = String.valueOf(c[i]);
                    break;
                }
            }
            if ("".equals(v)) {
                System.out.println("-1");
            } else {
                System.out.println(v);
            }
        }
    }
}