1380.md

1380. Lucky Numbers in a Matrix

Solution 1 (time O(mn), space O(m+n))

class Solution(object):
    def luckyNumbers (self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: List[int]
        """
        m, n = len(matrix), len(matrix[0])
        min_x = [float("inf") for _ in range(m)]
        max_y = [-float("inf") for _ in range(n)]
        for i in range(m):
            for j in range(n):
                min_x[i] = min(min_x[i], matrix[i][j])
                max_y[j] = max(max_y[j], matrix[i][j])
        ans = []
        for i in range(m):
            for j in range(n):
                if matrix[i][j] == min_x[i] and matrix[i][j] == max_y[j]:
                    ans.append(matrix[i][j])
        return ans