[LeetCode]Decode String@Python

最新推荐文章于 2024-06-19 18:22:32 发布

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最新推荐文章于 2024-06-19 18:22:32 发布

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分类专栏： leetcode stack 文章标签： leetcode python

本文链接：https://blog.youkuaiyun.com/byr_wy/article/details/90733456

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本文介绍了一种字符串解码算法，该算法能解析如'3[a]2[bc]'这样的编码字符串，并返回其解码后的结果'aaabcbc'。算法通过使用栈结构，有效地处理了嵌套的重复字符和数字，实现了复杂编码字符串的正确解码。

Decode String
Given an encoded string, return it’s decoded string.

The encoding rule is: k[encoded_string], where the encoded_string inside the square brackets is being repeated exactly k times. Note that k is guaranteed to be a positive integer.

You may assume that the input string is always valid; No extra white spaces, square brackets are well-formed, etc.

Furthermore, you may assume that the original data does not contain any digits and that digits are only for those repeat numbers, k. For example, there won’t be input like 3a or 2[4].

Example
s = “3[a]2[bc]”, return “aaabcbc”.
s = “3[a2[c]]”, return “accaccacc”.
s = “2[abc]3[cd]ef”, return “abcabccdcdcdef”.

Solution

class Solution:
    def decodeString(self, s: str) -> str:
        stack = []
        alpha, digit = '', ''
        for c in s:
            if c.isdigit():
                digit += c
            elif c=='[':
                stack.append([alpha, int(digit)])
                alpha, digit = '', ''
            elif c==']':
                m, n = stack.pop()
                alpha = m + alpha*n
            elif c.isalpha():
                alpha += c
        return alpha