Urlify

1class Solution:
2    def urlify(self, s, length):
3        res = []
4        for c in s:
5            if c == " ":
6                if res and res[-1] == "%20": continue
7                res.append("%20")
8            else: res.append(c)
9        if res and res[-1] == "%20": res.pop()
10
11        return "".join(res)
12
13sol = Solution()
14print(sol.urlify("Mr John Smith       ", 13))
15