题目链接：https://leetcode-cn.com/problems/ti-huan-kong-ge-lcof/
请实现一个函数，把字符串 s 中的每个空格替换成"%20"。
输入：s = “We are happy.”
输出：“We%20are%20happy.”
方法一：replace函数
难道题目是让我掌握 replace吗？
class Solution {
public String replaceSpace(String s) {
return s.replace(" ", "%20");
}
}
方法二：双百实现replace
class Solution {
public String replaceSpace(String s) {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < s.length(); i++){
char c = s.charAt(i);
if (c == ' '){
sb.append("%20");
}else{
sb.append(c);
}
}
return sb.toString();
}
}
