python leetcode 解码字母到整数映射【简单题】

1.读懂题目

2. 分析，推导解法，产生思路。

解题思路：遍历，三个为一组进行考察。第3个字符为‘#’则转换‘xx#’;第三个字符不为'#'则转换第一个字符。

3.代码实现

    def freqAlphabets1(self, s):
        """
        :type s: str
        :rtype: str
        """
  
        def change(strs):
            return chr(int(strs) + 96)
        i = 0
        res =''

        while i < len(s):
            if i +2 <len(s) and s[i+2] =='#':
                print(s[i:i+2])
                res += change(s[i:i+2])
                i += 2
            else:
                res += change(s[i])
            i += 1
        return res

    def freqAlphabets2(self, s: str) -> str:
        res = ""
        cur = 0
        while cur < len(s):
            if cur + 2 < len(s) and s[cur + 2] == '#':
                res += chr(96 + int(s[cur:cur + 2]))
                cur = cur + 3
                continue
            else:
                res += chr(96 + int(s[cur]))
                cur += 1
        return res