计蒜客 - T1212 仙岛求药

https://vjudge.net/problem/%E8%AE%A1%E8%92%9C%E5%AE%A2-T1212

AC代码

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
int n,m;
int sx,sy;
int tx,ty;
char g[1500][1500];
struct node{
	int x,y,step;
}t1,t2;
int main()
{
	while(cin>>n>>m)
	{
		getchar();
		for(int i=1;i<=n;i++)
		{
			for(int j=1;j<=m;j++)
			{
				char ch;
				ch=getchar();
				while(ch!='.' && ch!='@' && ch!='#' && ch!='*')
					ch=getchar();
				g[i][j]=ch;
				if(g[i][j]=='@')
				{
					sx=i; sy=j;
				}
				else if(g[i][j]=='*')
				{
					tx=i; ty=j;
				}
			}
		}

		queue<node> q;
		t1.x=sx;
		t1.y=sy;
		t1.step=0;
		q.push(t1);
		
		//出发点是否标记 
		g[sx][sy]='#';
		int dt[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
		while(q.size())
		{
			t1=q.front();
			q.pop();
			
			int f=0;
			for(int i=0;i<4;i++)
			{
				int dx=dt[i][0]+t1.x;
				int dy=dt[i][1]+t1.y;
				
				if(dx>0 && dx<=n && dy>0 && dy<=m && g[dx][dy]!='#')
				{
					t2.x=dx; 
					t2.y=dy;
					t2.step=t1.step+1;
					q.push(t2);
					
					if(g[dx][dy]=='*')
					{
						f=1;
						break;
					}
					else
						g[dx][dy]='#';

				}
			}
			if(f)
				break;
		}
		if(q.size())
			cout<<q.back().step<<endl;
		else
			cout<<"-1"<<endl;
	}
	return 0;
}