Python 6 lines O(N * |mines|) with explanation. Easy to understand
g[x][y] is the largest plus sign allowed centered at position (x, y). When no mines are presented, it is only limited by the boundary and should be something si
`g[x][y]` is the largest plus sign allowed centered at position (x, y). When no mines are presented, it is only limited by the boundary and should be something similar to\n```\n1 1 1 1 1\n1 2 2 2 1\n1 2 3 2 1\n1 2 2 2 1\n1 1 1 1 1\n```\nEach mine would affect the row and column it is at, causing the value of `g[x][y]` to be no larger than the distance between (x, y) and the mine.\n```\nclass Solution(object):\n    def orderOfLargestPlusSign(self, N, mines):\n        """\n        :type N: int\n        :type mines: List[List[int]]\n        :rtype: int\n        """\n        g = [[min(i, N-1-i, j, N-1-j) + 1 for j in range(N)] for i in range(N)]\n        for (x, y) in mines:\n            for i in range(N):\n                g[i][y] = min(g[i][y], abs(i - x))\n                g[x][i] = min(g[x][i], abs(i - y))\n        return max([max(row) for row in g])\n```
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