카테고리 없음
백준 14502 - 연구소 (java)
jin_j_i_n
2021. 4. 14. 13:57
www.acmicpc.net/status?user_id=dkwlsfk22&problem_id=14502&from_mine=1
채점 현황
www.acmicpc.net
백트래킹 + bfs로 풀었다.
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import java.io.*;
import java.util.*;
public class B14502 {
static int[] dx = { 0, -1, 0, +1 };
static int[] dy = { -1, 0, +1, 0 };
public static class Point {
int x;
int y;
public Point(int x, int y) {
this.x = x;
this.y = y;
}
}
static int N; static int M ;
static Point[] list = new Point[3];
static int max = 0;
static int[][] room;
public static void backTracking(int cnt) {
// System.out.println("cnt : "+cnt);
if ( cnt == 3 ) {
max = Math.max(bfs(), max) ;
return;
}else {
for(int i=0 ; i<N ; i++) {
for(int j=0 ; j<M; j++) {
// System.out.println("i : "+i+" , j: "+j);
if(room[i][j] == 0) {
room[i][j] = 1;
backTracking(cnt+1);
room[i][j] = 0;
}
}
}
}
return;
}
public static int bfs() {
Queue<Point> que = new LinkedList<Point>();
boolean[][] visit = new boolean[N][M];
int[][] count = new int[N][M];
for(int i=0 ; i<N ; i++) {
for(int j =0 ; j<M; j++) {
count[i][j] = -1;
}
}
for (int i = 0; i < N; i++) {
for (int j = 0; j < M; j++) {
if (room[i][j] == 2) {
que.add(new Point(i, j));
visit[i][j] = true;
}
}
}
while(!que.isEmpty()) {
Point tmp = que.poll();
visit[tmp.x][tmp.y] = true;
for(int i=0; i<4; i++) {
int nx = tmp.x + dx[i];
int ny = tmp.y + dy[i];
if(nx >= 0 && nx < N && ny >=0 && ny < M && !visit[nx][ny] && room[nx][ny] != 1) {
count[nx][ny] = count[tmp.x][tmp.y] + 1;
que.add(new Point(nx, ny));
}
}
}
int safe = 0;
for(int i=0 ; i<N; i++) {
for(int j=0; j<M ; j++) {
//바이러스가 아니고 , 벽이 아니어야 함
if(room[i][j] != 1 && count[i][j] == -1 && room[i][j] != 2) {
safe += 1;
}
}
}
// System.out.println("safe : "+safe);
return safe;
}
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String[] inputs = br.readLine().split(" ");
N = Integer.parseInt(inputs[0]);
M = Integer.parseInt(inputs[1]);
room = new int[N][M];
boolean[][] visit = new boolean[N][M];
for (int i = 0; i < N; i++) {
inputs = br.readLine().split(" ");
for (int j = 0; j < M; j++) {
room[i][j] = Integer.parseInt(inputs[j]);
}
}
backTracking(0);
System.out.println(max);
}
}
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