[Swift] 백준 - 바이러스

https://www.acmicpc.net/problem/2606

 

 

import Foundation

func main() {
    // 언래핑
    guard let V = Int(readLine()!), let N = Int(readLine()!) else { return }
    
    var graph = [[Int]](repeating: [], count: V+1)
    for _ in 0..<N{
        let XY = readLine()!.split(separator: " ").map { Int($0)! }
        let x = XY[0]
        let y = XY[1]
        
        graph[x].append(y)
        graph[y].append(x)
    }
    
    func bfs() {
        var visited = [Bool](repeating: false, count: V+1)
        var queue = [Int]()
        var result = 0
        queue.append(1)
        
        while !queue.isEmpty{
            let node = queue.removeFirst()
            
            if !visited[node]{
                visited[node] = true
                result += 1
                for i in graph[node]{
                    queue.append(i)
                }
                
            }
            
            
        }
        
        print(result-1)
        
    }
    
    bfs()
    
}

// main 함수 실행
main()