1380-LuckyNumbersInAMatrix.go

package main

// 1380. Lucky Numbers in a Matrix
// Given an m x 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]
// Explanation: 7 is the only lucky number since it is the minimum in its row and the maximum in its column.
 
// 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.

import "fmt"
import "slices"

func luckyNumbers (matrix [][]int) []int {
    res, n := []int{}, len(matrix)
    for i := 0; i < n; i++ {
        idx, flag, mn := 0, true, slices.Min(matrix[i]) // 找每一行的最小值
        for k, v := range matrix[i] { // 找最小值所在的下标
            if mn == v {
                idx = k 
            }
        }
        for j := 0; j < n; j++ {
            if matrix[j][idx] > mn { // 需要在同一列的所有元素中最大
                flag = false
                break
            }
        }
        if flag {
            res = append(res, mn)
        }
    }
    return res
}

func main() {
    // 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.
    fmt.Println(luckyNumbers([][]int{{3,7,8},{9,11,13},{15,16,17}})) // [15]
    // 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.
    fmt.Println(luckyNumbers([][]int{{1,10,4,2},{9,3,8,7},{15,16,17,12}})) // [12]
    // Example 3:
    // Input: matrix = [[7,8],[1,2]]
    // Output: [7]
    // Explanation: 7 is the only lucky number since it is the minimum in its row and the maximum in its column.
    fmt.Println(luckyNumbers([][]int{{7,8},{1,2}})) // [7]
}