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# Runtime: 205 ms (Top 93.96%) | Memory: 14.3 MB (Top 84.02%)
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class Solution:
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    def findBall(self, grid: List[List[int]]) -> List[int]:
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        m, n = len(grid), len(grid[0])
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        for i in range(m):
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            grid[i].insert(0, 1)
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            grid[i].append(-1)
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        res = []
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        for k in range(1, n + 1):
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            i, j = 0, k
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            struck = False
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            while i < m:
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                if grid[i][j] == 1:
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                    if grid[i][j + 1] == 1:
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                        j += 1
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                    else:
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                        struck = True
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                        break
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                else:
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                    if grid[i][j - 1] == -1:
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                        j -= 1
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                    else:
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                        struck = True
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                        break
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                i += 1
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            if struck:
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                res.append(-1)
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            else:
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                res.append(j - 1)
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        return res