bzoj1927[Sdoi2010]星际竞速

费用流,拆成二分图处理加上S和T直接搞

不用调试1A开心

/**************************************************************
    Problem: 1927
    User: BPM136
    Language: C++
    Result: Accepted
    Time:2216 ms
    Memory:2028 kb
****************************************************************/
 
#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<cstdlib>
#include<algorithm>
#include<bitset>
#define LL long long
#define fo(i,a,b) for(int i=a;i<=b;i++)
#define efo(i,x) for(int i=last[x];i!=0;i=e[i].next)
using namespace std;
inline LL read()
{
    LL d=0,f=1;char s=getchar();
    while(s<'0'||s>'9'){if(s=='-')f=-1;s=getchar();}
    while(s>='0'&&s<='9'){d=d*10+s-'0';s=getchar();}
    return d*f;
}
#define N 805
#define M 15005
#define inf 1000000000
struct edge
{
    int y,f,c,next;
}e[M*3];
int last[N*2],ne=1;
int n,m,ans=0;
int S,T;
 
int dis[N*2],lo[N*2],pre[N*2];
int q[N*9];
bitset<N*2>inq;
bool spfa(int s,int tt)
{
    memset(pre,0,sizeof(pre));
    memset(lo,0,sizeof(lo));
    fo(i,0,N*2-1)dis[i]=inf;
    inq.reset();
    int h=0,t=1;
    inq[s]=1;q[1]=s;dis[s]=0;
    while(h<t)
    {
        int now=q[++h];
        efo(i,now)
        if(e[i].f&&dis[now]+e[i].c<dis[e[i].y])
        {
            dis[e[i].y]=dis[now]+e[i].c;
            lo[e[i].y]=i;
            pre[e[i].y]=now;
            if(inq[e[i].y]==0)
            {
                inq[e[i].y]=1;
                q[++t]=e[i].y;
            }
        }
        inq[now]=0;
    }
    if(dis[tt]==inf)return 0;
    else return 1;
}
 
void mcf(int s,int t)
{
    while(spfa(s,t))
    {
        int x=t,mi=inf;
        while(pre[x]!=0)
        {
            mi=min(mi,e[lo[x]].f);
            x=pre[x];
        }
        x=t;
        while(pre[x]!=0)
        {
            ans+=mi*e[lo[x]].c;
            e[lo[x]].f-=mi;
            e[lo[x]^1].f+=mi;
            x=pre[x];
        }
    }
}
 
void add(int x,int y,int f,int c)
{
    e[++ne].y=y;e[ne].f=f;e[ne].c=c;e[ne].next=last[x];last[x]=ne;
}
 
void add2(int x,int y,int f,int c)
{
    add(x,y,f,c);add(y,x,0,-c);
}
 
void init()
{
    n=read(),m=read();
    S=2*n+1;T=S+1;
    fo(i,1,n)
    {
        int x=read();
        add2(S,i+n,1,x);
    }
    fo(i,1,m)
    {
        int x=read(),y=read(),w=read();
        if(x>y)swap(x,y);
        add2(x,y+n,1,w);
    }
    fo(i,1,n)
    {
        add2(S,i,1,0);
        add2(n+i,T,1,0);
    }
}
 
int main()
{
    init();
    mcf(S,T);
    cout<<ans<<endl;
    return 0;
}


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