优先队列

决定桶的容量是那个最短板#include<iostream>#include<cstdio>#include<cstring>#include<queue>using namespace std;typedef long long LL;int n,m;LL ans;int a[350][350];int book[350][350];int _next[4][2]={0,1,1,0,0,-1,-1,0};struct Node{    int x,y,value;    friend bool operator < (Node p,Node q)    {        return p.value>q.value;    }};priority_queue<Node>que;void dfs(int x,int y,int w){ que.pop();     for(int i=0;i<4;i++)     {        int tx=x+_next[i][0],ty=y+_next[i][1];        if(tx<1||tx>n||ty<1||ty>m||book[tx][ty]) continue;        book[tx][ty]=1;        if(a[tx][ty]<w)        {          ans=ans+w-a[tx][ty];          Node temp;temp.x=tx,temp.y=ty,temp.value=w;          que.push(temp);        }        else        {             Node temp;temp.x=tx,temp.y=ty,temp.value=a[tx][ty];             que.push(temp);        }     }     if(!que.empty()) dfs(que.top().x,que.top().y,que.top().value);}int main(){    while(scanf("%d%d",&m,&n)!=EOF)    {        memset(book,0,sizeof(book));        for(int i=1;i<=n;i++)         for(int j=1;j<=m;j++)           scanf("%d",&a[i][j]);         while(!que.empty()) que.pop();         ans=0;         for(int j=2;j<=m-1;j++)         {             Node temp;             temp.x=1,temp.y=j,temp.value=a[1][j];             que.push(temp);             temp.x=n,temp.y=j,temp.value=a[n][j];             que.push(temp);             book[1][j]=book[n][j]=1;         }         for(int i=2;i<=n-1;i++)         {             Node temp;             temp.x=i,temp.y=1,temp.value=a[i][1];             que.push(temp);             temp.x=i,temp.y=m,temp.value=a[i][m];             que.push(temp);             book[i][1]=book[i][m]=1;         }         book[1][1]=book[n][1]=book[1][m]=book[n][m]=1;         if(!que.empty())  //poj要加这个，，数据违规给小于3的数据。。不加re        dfs(que.top().x,que.top().y,que.top().value);         printf("%lld\n",ans);    }    return 0;}