[백준] 1926 그림 - Graph Theory / Java

• 문제 링크

1926번: 그림

 

• 풀이 과정

 

• 풀이 코드

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.StringTokenizer;

public class Main {

    static int n, m, max, size;
    static int[][] map;
    static boolean[][] visit;
    static int[] dy = {-1, 1, 0, 0};
    static int[] dx = {0, 0, -1, 1};

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        StringTokenizer st = new StringTokenizer(br.readLine());

        n = Integer.parseInt(st.nextToken());
        m = Integer.parseInt(st.nextToken());

        map = new int[n][m];
        visit = new boolean[n][m];

        for (int i = 0; i < n; i++) {
            st = new StringTokenizer(br.readLine());
            for (int j = 0; j < m; j++)
                map[i][j] = Integer.parseInt(st.nextToken());
        }

        int cnt = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (!visit[i][j] && map[i][j] != 0) {
                    size = 1;
                    dfs(i, j);

                    cnt++;
                    max = size > max ? size : max;
                }
            }
        }

        bw.write(cnt + "\n" + max);
        bw.flush();
    }

    private static void dfs(int y, int x) {
        visit[y][x] = true;

        for (int i = 0; i < 4; i++) {
            int ny = y + dy[i];
            int nx = x + dx[i];

            if (ny < 0 || ny >= n || nx < 0 || nx >= m)
                continue;
            if (!visit[ny][nx] && map[ny][nx] != 0) {
                size++;
                dfs(ny, nx);
            }
        }
    }

}