---
link: https://leetcode.com/problems/lucky-numbers-in-a-matrix/
tags: array, matrix, easy
---

# 1380. Lucky Numbers in a Matrix

## Question
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: Python

class Solution(object):
    def luckyNumbers (self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: List[int]
        """
        min_row = [float('inf') for _ in matrix]
        max_col = [float('-inf') for _ in matrix[0]]
        
        for row_index in xrange(len(matrix)):
            for col_index in xrange(len(matrix[row_index])):
                min_row[row_index] = min(min_row[row_index], matrix[row_index][col_index])
                max_col[col_index] = max(max_col[col_index], matrix[row_index][col_index])
           
        result = []
        for i in xrange(len(min_row)):
            for j in xrange(len(max_col)):
                if min_row[i] == max_col[j]:
                    result.append(min_row[i])
        return result
    
        

## Solution: Java