题解 | #数字颠倒#

考察的是颠倒，可以采用左右指针，字符串不可变，转成字符数组，最后用String的一个静态方法把字符数组组合成字符串

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        char[] chars = scanner.nextLine().toCharArray();
        int len = chars.length;
        int left = 0, right = len - 1;
        while (left < right) {
            char temp = chars[left];
            chars[left] = chars[right];
            chars[right] = temp;
            left ++;
            right --;
        }
        System.out.println(String.valueOf(chars));
    }

}