[BOJ] 1012 : 유기농배추

문제 >> 1012 : 유기농배추

dfs를 이용

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;
 
public class Main_1012 {
//유기농 배추
    
    static int[][] map;
    static int[] dy = {0,0,-1,1};
    static int[] dx = {-1,1,0,0};
    static int M,N;
    
    
    public static void main(String[] args) throws Exception {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        
        int T = Integer.parseInt(bf.readLine());
        
        for(int tc=1;tc<=T;tc++) {
            
            StringTokenizer st = new StringTokenizer(bf.readLine()," ");
            M = Integer.parseInt(st.nextToken()); //가로
            N = Integer.parseInt(st.nextToken()); //세로
            int K = Integer.parseInt(st.nextToken()); //배추개수
            
            map = new int[N][M];
            
            
            
            for(int i=0;i<K;i++) {
                st = new StringTokenizer(bf.readLine()," ");
                int x = Integer.parseInt(st.nextToken());
                int y = Integer.parseInt(st.nextToken());
                map[y][x]=1;
            }
            
            int ans=0;
            for(int i=0;i<N;i++) {
                for(int j=0;j<M;j++) {
                    if(map[i][j] == 1) {
                        dfs(i,j);
                        ans++;
                    }
                }
            }
            System.out.println(ans);
        }//end of tc
    }
 
 
    static void dfs(int y, int x) {
        map[y][x]=0; //visited check
        
        for(int i=0;i<4;i++) {
            int ny = y+dy[i];
            int nx = x+dx[i];
            
            if(ny<0 || ny>N-1 || nx<0 || nx>M-1) continue;
            if(map[ny][nx] == 1) dfs(ny,nx);
        }
        
        return ;
    }
}