백준 2573번 C++

#include <iostream>
#include <string>
#include <queue>
#include <cstring>

using namespace std;
const int MAX = 301;
int n, m;
int map[MAX][MAX];
queue<pair<int, int>> q;
int visited[MAX][MAX];
int copys[MAX][MAX];

struct Move {
	int x, y;
};
Move mv[4] = { {1,0}, {-1,0} ,{0,1}, {0,-1} };

bool divide() {
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			if (copys[i][j] > 0 && visited[i][j] == -1) 
				return true;
		}
	}
	return false;
}

void bfs() {

	while (!q.empty()) {
		int currenti = q.front().first;
		int currentj = q.front().second;
		q.pop();
		visited[currenti][currentj] = 1;

		if (map[currenti][currentj] == 0)
			continue;

		for (int k = 0; k < 4; k++) {
			int movei = currenti + mv[k].x;
			int movej = currentj + mv[k].y;

			if (movei >= 0 && movei < n && movej >= 0 && movej < m) {
				if (copys[movei][movej] == 0 && map[currenti][currentj] >=1) 
					map[currenti][currentj] -= 1;

				if (map[movei][movej] != 0 && visited[movei][movej] == -1) {
					q.push(make_pair(movei, movej));
					visited[movei][movej] = 1;
				}
			}
		}
	}
	return;
}

int main(void) {
	int counts,answer = 0;	
	cin >> n >> m;

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			cin >> map[i][j];
		}
	}
	while (true) {
		counts = 0;
		memset(visited, -1, sizeof(visited));
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < m; j++) {
				copys[i][j] = map[i][j];
				if (map[i][j] != 0 && counts == 0) {
					q.push(make_pair(i, j));
					counts++;
				}
			}
		}
		if (q.size() == 0) {
			answer = 0;
			break;
		}
		bfs();
		if (divide())
			break;
		answer++;
	}
	cout << answer << endl;
	return 0;
}