Alphabet Board Path LeetCode solution in Python

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# Runtime: 68 ms (Top 16.25%) | Memory: 14 MB (Top 13.50%)
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class Solution:
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    def alphabetBoardPath(self, target: str) -> str:
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        def shortestPath(r, c, tr, tc):
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            path = ""
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            pr = r
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            while r > tr:
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                path += "U"
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                r -= 1
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            while r < tr:
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                path += "D"
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                r += 1
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            if tr == 5 and pr != tr:
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                path = path[: len(path) - 1]
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            while c > tc:
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                path += "L"
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                c -= 1
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            while c < tc:
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                path += "R"
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                c += 1
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            if tr == 5 and pr != tr:
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                path = path + "D"
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            return path
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        table = ["abcde", "fghij", "klmno", "pqrst", "uvwxy", "z"]
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        r, c = 0, 0
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        ans = ""
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        for character in target:
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            t_row = None
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            for i, word in enumerate(table):
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                if character in word:
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                    t_row = i
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                    break
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            t_col = table[i].index(character)
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            ans += shortestPath(r, c, t_row, t_col) + "!"
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            r, c = t_row, t_col
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        return ans