rt
陷入无限递归

#include<bits/stdc++.h>
using namespace std;
char c[105][105];
int n,m;
bool dfs(int x,int y){
	if(c[x][y] == '#'){
		return false;
	}
	if(x == n && y == m){
		return true;
	}
	if(x < 1 || y < 1 || x > n || y > m){
		return false;
	}
	bool u = dfs(x-1,y),l = dfs(x,y-1),r = dfs(x,y+1),d = dfs(x+1,y);
	bool res = u || l || r || d;
	return res;
}
int main(){
	cin>>n>>m;
	for(int i = 1;i <= n;i ++){
		for(int j = 1;j <= m;j ++){
			cin>>c[i][j];
		}
	}
	bool tmpv = dfs(1,1);
	tmpv?cout<<"Yes":cout<<"No";
}