leetcode

Decode String

Decode String

stack version - 32ms

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class Solution:
    def decodeString(self, s):
        """
        :type s: str
        :rtype: str
        """
        stack = []
        stack.append(["", 1])
        num = ""
        for ch in s:
            if ch.isdigit():
              num += ch
            elif ch == '[':
                stack.append(["", int(num)])
                num = ""
            elif ch == ']':
                st, k = stack.pop()
                stack[-1][0] += st*k
            else:
                stack[-1][0] += ch
        return stack[0][0]

test code

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In [109]: s = Solution(); t = s.decodeString("3[a]2[bc]"); print(t)
aaabcbc

leet code