题解 | #走迷宫#

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
#define IOS ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define int long long
#define double long double
const int N=0x3f3f3f3f,mod=1e9+7;
struct node
{
	int x;
	int y;
	string path;
};
signed main()
{
	IOS;
	int n,m;
	cin>>n>>m;
	char mp[1010][1010];
	char k[4]={'D','L','R','U'};
	int dir[4][2]={{1,0},{0,-1},{0,1},{-1,0}};
	int vis[1010][1010];
	for(int i=0;i<n;i++)
	{
		cin>>mp[i];
	}
	node start;
	int a,b;
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<m;j++)
		{
			if(mp[i][j]=='$')
			{
				a=i;
				b=j;
				break;
			}
		}
	}
	start.x=a;
	start.y=b;
	start.path="";
	vis[a][b]=1;
	queue<node>q;
	q.push(start);
	while(!q.empty())
	{
		node now=q.front();
		q.pop();
		if(now.x==n-1||now.y==m-1||now.x==0||now.y==0)
		{
			cout<<now.path.size()<<endl;
			return 0;
		}
		for(int i=0;i<4;i++)
		{
			node next;
			next.x=now.x+dir[i][0];
			next.y=now.y+dir[i][1];
			if(next.x<0||next.x>=n||next.y<0||next.y>=m)
			continue;
			if(vis[next.x][next.y]==1||mp[next.x][next.y]=='#')
			continue;
			vis[next.x][next.y]=1;
			next.path=now.path+k[i];
			q.push(next);
		}
	}
	cout<<"-1"<<endl;
	return 0;
}