【BFS】A - Red and Black POJ - 1979

曾经终败给现在 2023-06-13 09:49 5阅读 0赞

[A - Red and Black POJ - 1979][]  
bfs模板

#include<cstdio>
    #include<cstring>
    #include<algorithm>
    #include<cmath>
    #include<iostream>
    #include<set>
    #include<queue>
    using namespace std;
    #define ll long long
    int dir[4][2]={
        0,1,1,0,-1,0,0,-1};
    int vis[30][30];
    char c[30][30];
    int h,w,ans;
    struct wwr
    {
        
        int x,y;
    };
    void bfs(int x,int y)
    {
        
        memset(vis,0,sizeof(vis));
        queue<wwr>q;
        wwr s;
        s.x=x;
        s.y=y;
        q.push(s);
        ans=1;
        vis[x][y]=1;
        while(!q.empty())
        {
        
            wwr a,b;
            a=q.front();
            q.pop();
            for(int i=0;i<4;i++)
            {
        
                b.x=a.x+dir[i][0];
                b.y=a.y+dir[i][1];
                if(b.x>=h||b.y>=w||b.x<0||b.y<0||c[b.x][b.y]=='#'||vis[b.x][b.y])
                    continue;
                vis[b.x][b.y]=1;
                ans++;
                q.push(b);
            }
        }
    }
    int main()
    {
        
        while(~scanf("%d%d",&w,&h))
        {
        
            if(w==0&h==0)
                break;
            for(int i=0;i<h;i++)
                scanf("%s",c[i]);
            for(int i=0;i<h;i++)
                for(int j=0;j<w;j++)
                    if(c[i][j]=='@')
                    {
        
                        bfs(i,j);
                        printf("%d\n",ans);
                        break;
                    }
        }
        return 0;
    }

[A - Red and Black POJ - 1979]: https://vjudge.net/contest/339651#problem/A