hdu_1728_逃离迷宫

原题链接：http://acm.hdu.edu.cn/showproblem.php?pid=1728

#include <iostream>
#include <queue>
using namespace std;
int r,c,k,visit[101][101];
char map[101][101];
int dir_x[4] = {0,1,0,-1},dir_y[4] = {1,0,-1,0};
typedef struct 
{
	int x;
	int y;
	int turn;//转弯次数 
}node;

node s,e;

void bfs()
{
	queue<node> que;
	node first,next;
	if(s.x == e.x && s.y == e.y)//特殊情况，起点和终点相同 
	{
		cout << "yes" << endl;
		return;
	}
	s.turn = -1;//初始化起点的方向为-1，即起点到四周的转弯次数为0 
	que.push(s);
	 
	while(!que.empty())
	{
		first = que.front();
		que.pop();
		if(first.x == e.x && first.y == e.y && first.turn <= k)
		{
			cout << "yes" << endl;
			return;
		}
		int i;
		for(i = 0;i < 4;i++)
		{
			next.x = first.x + dir_x[i];
			next.y = first.y + dir_y[i];
			while(next.x >= 1 && next.x <= r && next.y >= 1 && next.y <= c && map[next.x][next.y] == '.')
			{
				if(visit[next.x][next.y] == 0)//没被访问过 
				{
					next.turn = first.turn + 1;
					visit[next.x][next.y] = 1;//标记已经访问过了 
					que.push(next);
				}
				next.x += dir_x[i];//确定一个方向，一直朝这个方向走，直到不能走位置才改变方向 
				next.y += dir_y[i];
			}
		}
	}
	cout << "no" << endl;
	return;
}
int main(int argc, char *argv[])
{
	int t,i,j,x1,y1,x2,y2;
	cin >> t;
	while(t--)
	{
		memset(visit,0,sizeof(visit));
		cin >> r >> c;
		for(i = 1;i <= r;i++)
			for(j = 1;j <= c;j++)
				cin >> map[i][j];
		cin >> k >> x1 >> y1 >> x2 >> y2;
		s.x = y1;
		s.y = x1;
		e.x = y2;
		e.y = x2;
		bfs();
	}
	return 0;
}