JZ2 替换空格

char[] string = s.toCharArray();

return new String(res,0,j);

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
     *
     * 
     * @param s string字符串 
     * @return string字符串
     */
    public String replaceSpace (String s) {
        int len = s.length();
        char[] string  = s.toCharArray();
        char[] res = new char[len*3];

        int j =0;
        for(int i=0; i<len;i++){
            if(string[i]!=' '){
                res[j++] = string[i];
            }
            else{
                res[j++] = '%';
                res[j++] = '2';
                res[j++] = '0';
            }
        }
        return new String(res,0,j);
    }
}