Expression Add Operators LeetCode solution in Python

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class Solution:
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    def addOperators(self, num: str, target: int) -> List[str]:
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        s = num[0]
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        q = ["+", "-", "*", ""]
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        ans = []
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        def cal(w):
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            i = 1
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            while i < len(w) - 1:
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                if w[i] == "*":
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                    q = int(w[i - 1]) * int(w[i + 1])
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                    del w[i + 1]
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                    del w[i]
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                    w[i - 1] = q
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                    continue
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                i += 2
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            i = 1
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            while i < len(w) - 1:
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                if w[i] == "+":
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                    q = int(w[i - 1]) + int(w[i + 1])
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                    del w[i + 1]
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                    del w[i]
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                    w[i - 1] = q
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                    continue
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                elif w[i] == "-":
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                    q = int(w[i - 1]) - int(w[i + 1])
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                    del w[i + 1]
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                    del w[i]
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                    w[i - 1] = q
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                    continue
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                i += 2
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            return w
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        def dfs(s, i):
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            nonlocal ans
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            if i == len(num):
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                x = ""
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                myl = []
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                for i in s:
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                    if i not in ["+", "-", "*"]:
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                        x += i
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                    else:
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                        myl.append(int(x))
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                        myl.append(i)
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                        x = ""
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                myl.append(int(x))
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                print(myl)
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                a = cal(myl)
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                print(a)
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                if a[0] == target:
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                    ans.append(s)
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                return
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            for j in q:
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                dfs(s + j + num[i], i + 1)
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        dfs(s, 1)
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        return ans