Escape the Spreading Fire LeetCode solution in Python

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class Solution(object):
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    def maximumMinutes(self, A):
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        m, n = len(A), len(A[0])
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        inf = 10**10
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        d = [[0, 1], [1, 0], [0, -1], [-1, 0]]
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        fires = [[i, j, 0] for i in range(m) for j in range(n) if A[i][j] == 1]
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        A = [[inf if a < 2 else -1 for a in r] for r in A]
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        def bfs(queue, seen):
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            for i, j, t in queue:
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                if seen[i][j] < inf:
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                    continue
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                seen[i][j] = t
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                for di, dj in d:
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                    x, y = i + di, j + dj
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                    if (
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                        0 <= x < m
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                        and 0 <= y < n
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                        and seen[x][y] >= inf
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                        and t + 1 < A[x][y]
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                    ):
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                        queue.append([x, y, t + 1])
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        def die(t):
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            seen = [[inf + 10] * n for i in range(m)]
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            bfs([[0, 0, t]], seen)
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            return seen[-1][-1] > A[-1][-1]
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        bfs(fires, A)
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        A[-1][-1] += 1
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        return bisect_left(range(10**9 + 1), True, key=die) - 1