[kuangbin带你飞]专题一简单搜索-J - Fire!

最新推荐文章于 2021-07-04 21:34:35 发布

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本文深入探讨了使用智能算法预测火势蔓延速度并指导逃生路径的问题。通过实现火势扩散模拟与路径搜索算法，文章提供了一种有效的方法来评估在火灾场景中如何快速安全地逃离危险区域。重点介绍了火势扩散速度计算、火势蔓延预测以及基于BFS（广度优先搜索）的最短逃生路径寻找策略。

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分析:先确定火的扩散速度，当J走到该格，若时间小于扩散到该格的时间则无事，否则烧死

#include <cstdio>
#include <queue>
#include <iostream>
#include <cstring>

using namespace std;
typedef long long ll;
typedef pair <int, int > P;
typedef struct {
	int a;
	int b;
	int wal;
}dat;
dat p;
queue <dat> f;
char temp[1005][1005];
int maze[1005][1005];
int n, m, ans, vis[1005][1005], dir[][2] = { 0,1, 1,0, 0,-1, -1,0 };
dat star;

void init()
{
	cin >> n >> m;
	//scanf("%d %d", &n, &m);
	ans = 100000; star.a = 0, star.b = 0;
	memset(vis, 0, sizeof vis);
	memset(maze, 0, sizeof maze);
	for (int i = 1; i <= n; i++)
		cin >> temp[i] + 1;
		//scanf("%s", temp[i] + 1);

	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
		{
			if (temp[i][j] == 'J')
			{
				star.a = i;
				star.b = j;
				maze[i][j] = 0;
			}
			if (temp[i][j] == '.')
				maze[i][j] = 0;
			if (temp[i][j] == '#')
				maze[i][j] = -1;
			if (temp[i][j] == 'F')
			{
				p.a = i, p.b = j;
				maze[i][j] = 0;
				vis[i][j] = 1;
				p.wal = 0;
				f.push(p);
			}
		}

	//vis[star.a][star.b] = 1;
}
void fire()
{
	dat now, nex;
	while (f.size())
	{
		now = f.front();
		f.pop();

		for (int i = 0; i<4; i++)
		{
			int a, b;
			a = now.a + dir[i][0], b = now.b + dir[i][1];
			nex.a = a, nex.b = b;
			nex.wal = now.wal + 1;
			if (1 <= a&&a <= n && 1 <= b&&b <= m)
				if (maze[a][b] == 0&&vis[a][b]==0)
				{
					maze[a][b] = now.wal + 1;
					f.push(nex);
					vis[a][b] = 1;
				}
		}
	}
}

void bfs()
{
	memset(vis, 0, sizeof vis);
	vis[star.a][star.b] = 1;
	queue <dat> q;
	star.wal = 0;
	q.push(star);
	// cout<<maze[1][1]<<endl;

	while (q.size())
	{
		dat now = q.front();
		q.pop();

		if (now.a == 0 || now.a>n || now.b == 0 || now.b>m)
		{
			if (ans > now.wal)
			{
				ans = now.wal;
				return;
			}
		}
		if (maze[now.a][now.b] <= now.wal&&maze[now.a][now.b]!=0 )
		{
			continue;
		}

		for (int i = 0; i<4; i++)
		{
			int a = now.a + dir[i][0], b = now.b + dir[i][1];
			dat nex;
			nex.a = a, nex.b = b;
			nex.wal = now.wal + 1;

			if (vis[nex.a][nex.b] == 0 && maze[nex.a][nex.b] != -1)
			{
				q.push(nex);
				vis[nex.a][nex.b] = 1;
			}
		}
	}
}

void solve()
{
	init();
	fire();
	bfs();
	if (ans != 100000)
		printf("%d\n", ans );
	else
		printf("IMPOSSIBLE\n");
}

int main(void)
{
	int t;
	cin >> t;

	while (t--)
	{
		solve();
	}
}