[LeetCode]#1380. Lucky Numbers in a Matrix

Environment: Python 3.7

Key technique: zip

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

Analysis:

1. Search minimum element in its row
2. Search maximum in its column.
3. Use logic “and” to find lucky number.

Solution:

class Solution:
    def luckyNumbers (self, matrix):
        min_n = {min(rows) for rows in matrix}
        max_n = {max(columns) for columns in zip(*matrix)} 
        
        return list(min_n & max_n)

Submissions:

Reference:

LeetCode | 1380. Lucky Numbers in a Matrix矩阵中的幸运数【Python】_Python_Wonz-CSDN博客

http://puremonkey2010.blogspot.com/2015/10/python-python-zip.html