불 (feat. 백준, 5427번)

불
https://www.acmicpc.net/problem/5427

5427번: 불

 

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// woohyeon.kim
// kim519620.tistory.com
#include <iostream>
#include <string.h>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;
int H, W, dx[4], dy[4];
char arr[1001][1001];
bool visit[1001][1001];
int ans[1001][1001];
vector<pair<int, int>> fires;
int bfs(register int x, register int y) {
	memset(visit, false, sizeof(visit));
	queue<pair<int, int>> q;
	for (auto& fire : fires) {
		q.push(fire);
		visit[fire.first][fire.second] = true;
		ans[fire.first][fire.second] = -1;
	}
	q.push(make_pair(x, y));
	visit[x][y] = true;
	ans[x][y] = 1;
	if (x == 1 || x == H || y == 1 || y == W)
		return ans[x][y];
	while (!q.empty()) {
		auto p = q.front(); q.pop();
		x = p.first, y = p.second;
		for (register int d = 0, nx, ny; d < 4; ++d) {
			nx = x + dx[d], ny = y + dy[d];
			if (1 <= nx && nx <= H && 1 <= ny && ny <= W && !visit[nx][ny] && arr[nx][ny] != '#') {
				visit[nx][ny] = true;
				ans[nx][ny] = ans[x][y];
				if (ans[nx][ny] != -1)
					ans[nx][ny] += 1;
				if((nx == 1 || nx == H || ny == 1 || ny == W) && (ans[nx][ny] != -1))
					return ans[nx][ny];
				q.push(make_pair(nx, ny));
			}
		}
	}
	return -1;
}
int main() {
	ios::sync_with_stdio(false), cin.tie(NULL);
	dx[0] = 1, dx[1] = -1, dx[2] = dx[3] = 0;
	dy[0] = dy[1] = 0, dy[2] = 1, dy[3] = -1;
	register int T;
	cin >> T;
	for (register int t = 0, x, y; t < T; ++t) {
		fires.clear();
		cin >> W >> H;
		for (register int h = 1, w; h <= H; ++h)
			for (w = 1; w <= W; ++w) {
				cin >> arr[h][w];
				if (arr[h][w] == '@')
					x = h, y = w;
				else if (arr[h][w] == '*')
					fires.push_back(make_pair(h, w));
			}
		auto ans = bfs(x, y);
		if (ans < 0)
			cout << "IMPOSSIBLE";
		else
			cout << ans;
		cout << "\n";
	}
	return 0;
}
// *&)*@*

 

 

아래 "불!" 과 동일한 문제입니다.

불! (feat. 백준, 4179번)