[프로그래머스] 네트워크

https://programmers.co.kr/learn/courses/30/lessons/43162

코딩테스트 연습 - 네트워크 | 프로그래머스

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import java.util.ArrayList;

class Solution {
    
    static boolean[] visited;
	static ArrayList<Integer>[] list;
	static int answer;
    
    public static int solution(int n, int[][] computers) {
		answer = 0;
		
		int len = computers[0].length;
		
		list = new ArrayList[len];
		visited = new boolean[len];
		
		for(int i=0; i<len; i++) list[i] = new ArrayList<Integer>();
		
		for(int i=0; i<computers.length; i++) {
			for(int j=0; j<computers[i].length; j++) {
				if(i == j || computers[i][j] == 0) continue;
				list[i].add(j);
			}
		}
		
		for(int i=0; i<len; i++) {
			if(!visited[i]) {
				DFS(i);
				answer++;
			}
		}
		
		return answer;
	}
	
	public static void DFS(int x) {
		visited[x] = true;
		
		for(int i=0; i<list[x].size(); i++) {
			int y = list[x].get(i);
			
			if(!visited[y]) DFS(y);
		}
		
	}
}