Find Kth Largest XOR Coordinate Value LeetCode solution in Python

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class Solution:
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    def kthLargestValue(self, matrix: List[List[int]], k: int) -> int:
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        temp = 0
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        pq = []
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        n = len(matrix)
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        m = len(matrix[0])
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        prefix = [[0] * m for i in range(n)]
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        for i in range(n):
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            for j in range(m):
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                if i == 0 or j == 0:
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                    if i == 0 and j == 0:
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                        prefix[i][j] = matrix[i][j]
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                    elif i == 0 and j != 0:
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                        prefix[i][j] ^= prefix[i][j - 1] ^ matrix[i][j]
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                    else:
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                        prefix[i][j] ^= prefix[i - 1][j] ^ matrix[i][j]
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                else:
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                    prefix[i][j] ^= (
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                        prefix[i - 1][j]
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                        ^ prefix[i][j - 1]
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                        ^ matrix[i][j]
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                        ^ prefix[i - 1][j - 1]
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                    )
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                if len(pq) < k:
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                    heappush(pq, prefix[i][j])
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                else:
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                    heappush(pq, prefix[i][j])
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                    heappop(pq)
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        return heappop(pq)