bzoj 1001: [BeiJing2006]狼抓兔子 平面图最小割

/**************************************************************
    Problem: 1001
    User: 96655
    Language: C++
    Result: Accepted
    Time:1724 ms
    Memory:95120 kb
****************************************************************/
 
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<iostream>
#include<cstdlib>
#include<queue>
#include<map>
#include<set>
#include<vector>
#include<cmath>
#include<stack>
#include<utility>
using namespace std;
const int maxn=1001000;
const int INF=0x3f3f3f3f;
struct Edge
{
    int v,w,next;
} edge[maxn*6];
int head[maxn*2],p,n,m,y;
void addedge(int u,int v,int w)
{
    edge[p].w=w;
    edge[p].v=v;
    edge[p].next=head[u];
    head[u]=p++;
}
struct asd
{
    int x,d;
    asd (int a,int b):x(a),d(b) {}
    bool operator<(const asd &e)const
    {
        return d>e.d;
    }
};
priority_queue<asd>q;
int dis[maxn*2],vis[maxn*2];
void Dijkstra(int s)
{
    memset(vis,0,sizeof(vis));
    while(!q.empty())q.pop();
    for(int i=0; i<=y; i++)
        dis[i]=INF;
    dis[s]=0;
    q.push(asd(s,0));
    while(!q.empty())
    {
        asd e=q.top();
        q.pop();
        if(vis[e.x])continue;
        vis[e.x]=1;
        for(int i=head[e.x]; i!=-1; i=edge[i].next)
        {
            int v=edge[i].v;
            if(dis[v]>dis[e.x]+edge[i].w)
            {
                dis[v]=dis[e.x]+edge[i].w;
                q.push(asd(v,dis[v]));
            }
        }
    }
}
void read(int &x)
{
    char c;
    while((c=getchar())<‘0‘ || c>‘9‘);
    x=c-‘0‘;
    while((c=getchar())>=‘0‘ && c<=‘9‘) x=(x<<3)+(x<<1)+c-‘0‘;
}
int main()
{
    read(n);
    read(m);
    if(n==1||m==1)
    {
        if(n>m)swap(n,m);
        int ans=INF,a;
        for(int i=1; i<m; i++)
        {
            scanf("%d",&a);
            ans=min(a,ans);
        }
        if(ans==INF)printf("0\n");
        else printf("%d\n",ans);
        return 0;
    }
    memset(head,-1,sizeof(head));
    p=0;
    y=(n-1)*(m-1)*2+1;
    int w,u,v;
    for(int i=1; i<=n; i++)
    {
        for(int j=1; j<m; j++)
        {
            read(w);
            if(i==1)
            {
                u=((i-1)*(m-1)+j)*2;
                addedge(u,y,w);
                addedge(y,u,w);
            }
            else if(i==n)
            {
                u=((i-2)*(m-1)+j)*2-1;
                addedge(0,u,w);
            }
            else
            {
                u=((i-1)*(m-1)+j)*2;
                v=((i-2)*(m-1)+j)*2-1;
                addedge(u,v,w);
                addedge(v,u,w);
 
            }
        }
    }
    for(int i=1; i<n; i++)
    {
        for(int j=1; j<=m; j++)
        {
            read(w);
            if(j==1)
            {
                u=((i-1)*(m-1)+j)*2-1;
                addedge(0,u,w);
                addedge(u,0,w);
 
            }
            else if(j==m)
            {
                u=((i-1)*(m-1)+j-1)*2;
                addedge(u,y,w);
                addedge(y,u,w);
 
            }
            else
            {
                u=((i-1)*(m-1)+j)*2-1;
                v=((i-1)*(m-1)+j-1)*2;
                addedge(u,v,w);
                addedge(v,u,w);
 
            }
        }
    }
    for(int i=1; i<n; i++)
    {
        for(int j=1; j<m; j++)
        {
            read(w);
            u=((i-1)*(m-1)+j)*2-1;
            v=((i-1)*(m-1)+j)*2;
            addedge(u,v,w);
            addedge(v,u,w);
        }
    }
    Dijkstra(0);
    printf("%d\n",dis[y]);
    return 0;
}