프로그래머스 2021 KAKAO BLIND RECRUITMENT 합승 택시 요금

import Foundation

func solution(_ n:Int, _ s:Int, _ a:Int, _ b:Int, _ fares:[[Int]]) -> Int {
    var matrix = Array(repeating: Array(repeating: Int(INT32_MAX), count: n), count: n)
    
    (0..<n).forEach {
        matrix[$0][$0] = 0
    }
    
    fares.forEach {
        matrix[$0[0]-1][$0[1]-1] = $0[2]
        matrix[$0[1]-1][$0[0]-1] = $0[2]
    }
        
    for k in 0..<n {
        for i in 0..<n {
            for j in 0..<n {
                if matrix[i][k] + matrix[k][j] < matrix[i][j] {
                    matrix[i][j] = matrix[i][k] + matrix[k][j]
                }
            }
        }
    }
    
    var answer = Int.max
    
    (0..<n).forEach {
        if answer > matrix[s-1][$0] + matrix[$0][a-1] + matrix[$0][b-1] {
            answer = matrix[s-1][$0] + matrix[$0][a-1] + matrix[$0][b-1]
        }
    }
    
    return answer
}