广度优先收索（T148526）

#include <iostream>
#include <queue>
using namespace std;
struct point
{
	int x,y,bu;
};
int sx=1,sy=1,ex,ey,m[1000][1000],b[1000][1000],ssx[100],ssy[100];
queue <point>t;
int main()
{
	int n,m2,v=0;cin>>n>>m2;
	ex=n;ey=m2;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m2;j++){
			char tmp;cin>>tmp;
			if(tmp=='.'){
				m[i][j]=1;
			}
			if(tmp=='#'){
				m[i][j]=0;
			}
			if(tmp=='$'){
				m[i][j]=3;
				ssx[v]=i;
				ssy[v]=j;
				v++;
			}
		}
	}
	int meet=0;
	point now,tmp;
	now.x=sx,now.y=sy,now.bu=0,b[now.x][now.y]=1;
	t.push(now);
	int aa[4][2]={{-1,0},{1,0},{0,1},{0,-1}};
	while(t.size()!=0){
		now=t.front();
		t.pop();
		if(now.x==ex && now.y==ey){
			cout<<b[now.x][now.y]+1;
			return 0;
		}
		if(m[now.x][now.y]==3 && meet==0){
			meet=1;
			for(int i=0;i<v;i++){
				tmp.x=ssx[i];
				tmp.y=ssy[i];
				tmp.bu=now.bu;
				t.push(tmp);
				b[now.x][now.y]=1;
			}
		}
		for(int i=0;i<4;i++){
			if(m[now.x+aa[i][0]][now.y+aa[i][1]] && b[now.x+aa[i][0]][now.y+aa[i][1]]==0){
				tmp.x=now.x+aa[i][0];
				tmp.y=now.y+aa[i][1];
				b[now.x+aa[i][0]][now.y+aa[i][1]]=b[now.x][now.y]+1;
				t.push(tmp);
			}
		}
	}
	cout<<-1;
	return 0;
}