题解 | 反转字符串

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 反转字符串
     * @param str string字符串 
     * @return string字符串
     */
    public String solve (String str) {
        // write code here
        if (str.isEmpty()) return str;
        char[] cs = str.toCharArray();
        int left = 0;
        int right = cs.length-1;
        while (left < right) {
            char c = cs[left];
            cs[left] = cs[right];
            cs[right] = c;
            left++;
            right--;
        }
        return new String(cs);
    }
}