[백준] 1743 음식물 피하기 (실버1)

https://www.acmicpc.net/problem/1743
14분 컷 - vis true 빼먹어서 좀 더 걸림

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    static int n,m,k, cnt;
    static int[][] trash;
    static boolean[][] vis;
    static int[] dx = {0,1,0,-1};
    static int[] dy = {1,0,-1,0};
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());

        n = Integer.parseInt(st.nextToken());
        m = Integer.parseInt(st.nextToken());
        k = Integer.parseInt(st.nextToken());
        trash = new int[n+1][m+1]; // 0번 index dummy
        vis = new boolean[n+1][m+1];

        for(int i=0;i<k;i++){
            st = new StringTokenizer(br.readLine());
            int r = Integer.parseInt(st.nextToken());
            int c = Integer.parseInt(st.nextToken());
            trash[r][c] = 1;
        }

        int max = Integer.MIN_VALUE;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=m;j++){
                if(trash[i][j] == 1 && !vis[i][j]){
                    cnt = 1;
                    dfs(i, j);
                    if(max<cnt){
                        max=cnt;
                    }
                }

            }
        }
        System.out.println(max);
    }

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

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

            if(nx<0 || nx>n || ny<0 || ny>m || vis[nx][ny] || trash[nx][ny] ==0) continue;
            vis[nx][ny] = true;
            dfs(nx,ny);
            cnt++;
        }
    }
}