嗨害嗨ac题解

/只因AC实在太美/
仅供参考请勿抄袭

#include<bits/stdc++.h>
using namespace std;
int n,m,a;
char mp[50][50];
bool vis[50][50];
int dx[4]={1,0,0,-1};
int dy[4]={0,-1,1,0};
struct node{int x,y,s;};
bool check(int x,int y){return x>=1 and x<=n and y>=1 and y<=m and mp[x][y]=='.' and !vis[x][y];}
int bfs(){
    vis[1][1]=1;
    queue<node>q;
    q.push({1,1,1});
    while(!q.empty()){
        node f=q.front();
        if(f.x==n and f.y==m)return a+1;
        a=f.s;
        q.pop();
        for(int i=0;i<4;i++){
            int nx=f.x+dx[i];
            int ny=f.y+dy[i];
            if(check(nx,ny)){
                q.push({nx,ny,f.s+1});
                vis[nx][ny]=1;
            }
        }
    }
    return a;
}
int main(){
    cin >> n >> m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin >> mp[i][j];
        }
    }
    cout << bfs();
}