题解 | #替换空格#

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) {
        // write code here
        int N = s.length();
        char[] arr = new char[3 * N];
        int size = N;
        for(int i = 0, j = 0; i < N; i++) {
            char c = s.charAt(i);
            if(c != ' ') {
                arr[j++] = c;
            } else {
                arr[j++] = '%';
                arr[j++] = '2';
                arr[j++] = '0';
                size += 2;
            }
        }
        return new String(arr, 0, size);
    }
}