1380. Lucky Numbers in a Matrix-矩阵中的幸运数

Given a m * n matrix of distinct numbers, return all lucky numbers in the matrix in any order.

A lucky number is an element of the matrix such that it is the minimum element in its row and maximum in its column.

Example 1:
Input: matrix = [[3,7,8],[9,11,13],[15,16,17]]
Output: [15]
Explanation: 15 is the only lucky number since it is the minimum in its row and the maximum in its column

Example 2:
Input: matrix = [[1,10,4,2],[9,3,8,7],[15,16,17,12]]
Output: [12]
Explanation: 12 is the only lucky number since it is the minimum in its row and the maximum in its column.

Example 3:
Input: matrix = [[7,8],[1,2]]
Output: [7]

Constraints:

• m == mat.length
• n == mat[i].length
• 1 <= n, m <= 50
• 1 <= matrix[i][j] <= 10^5.
• All elements in the matrix are distinct.

Solution in python:

class Solution:
    def luckyNumbers (self, matrix: List[List[int]]) -> List[int]:
        min_i = [min(matrix[i]) for i in range(len(matrix))]
        max_j = [max([matrix[i][j] for i in range(len(matrix))]) for j in range(len(matrix[0]))]
        result = []
        for i in range(len(matrix)):
            for j in range(len(matrix[0])):
                if matrix[i][j] == min_i[i] == max_j[j]:
                    result.append(matrix[i][j])
        return result