codevs1215 迷宫

用dfs做的，还不嫌累的用if，当然bfs也很好做（代码很丑）。

#include <cstdio>#include <cstring>#include <algorithm>#include <iostream>using namespace std;int n;bool flag;bool vis[50][50];char s[50][50];void dfs(int x,int y){    if(x == n&&y == n)    {        flag = 1;        return ;    }    vis[x][y] = 1;    if(s[x+1][y] == '.'&&!vis[x+1][y])    {        vis[x+1][y]=1;        dfs(x+1,y);    }    if(s[x-1][y] == '.'&&!vis[x-1][y])    {        vis[x-1][y]=1;        dfs(x-1,y);    }    if(s[x][y+1] == '.'&&!vis[x][y+1])    {        vis[x][y+1]=1;        dfs(x,y+1);    }    if(s[x][y-1] == '.'&&!vis[x][y-1])    {        vis[x][y-1]=1;        dfs(x,y-1);    }}int main(){    int t;    cin>>t;    for(int k = 1; k <= t; k ++)    {        flag = 0;        memset(vis,0,sizeof(vis));        cin>>n;        for(int i = 1; i <= n; i ++)        for(int j = 1; j <= n; j ++)        {            cin>>s[i][j];        }        for(int i = 1; i <= n; i ++)        for(int j = 1; j <= n; j ++)        {            if(s[i][j] == 's'||s[i][j] == 'e')            {                s[i][j] ='.';            }        }        dfs(1,1);        if(flag)        puts("YES");        else        puts("NO");    }    return 0;}