import java.util.*;
public class Solution {
/**
* 反转字符串
* @param str string字符串
* @return string字符串
*/
public String solve (String str) {
char[] chs = str.toCharArray();
StringBuilder sb = new StringBuilder();
for (int i = chs.length-1; i >=0 ; i--) {
sb.append(chs[i]);
}
return sb.toString();
}
}