NC103 反转字符串

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) {
        int len = str.length();
        char [] res = new char[len];
        for(int j=len-1; j>=0; j--){
            res[j] = str.charAt(len-1-j);
        }
        String str2 = new String(res);
        return str2;
    }
}

原地对半反转也不错

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) {
        int len = str.length();
        int i=0;
        int j =len-1;
        char[] strings = str.toCharArray();
        while(i<j){
            char temp = strings[i];
            strings[i] = strings[j];
            strings[j] = temp;
            i++;
            j--;
        }
        return new String(strings);
    }
}