题解 | #字符逆序#

要对String的内置char[]数组有深刻理解。反过来排序，for循环效率最高

import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner in  = new Scanner(System.in);
        while(in.hasNextLine()){
            String li = in.nextLine();
            char[] liArr = li.toCharArray();
            int len = liArr.length;
            StringBuilder builder = new StringBuilder();
            for(int i=0;i<len;i++){
                builder.append(liArr[len-i-1]);
            }
            System.out.println(builder);
        }
    }
}