bzoj3931[CQOI2015]网络吞吐量

天呐手贱打错了WA了N次好吧这不是重点

题意即题解

/**************************************************************
    Problem: 3931
    User: BPM136
    Language: C++
    Result: Accepted
    Time:216 ms
    Memory:7984 kb
****************************************************************/
 
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#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 f*d;
}
#define N 505
#define M 100005
#define inf 10000000000000LL
LL a[N][N];
struct edg
{
    int x,y;
    LL w;
}ee[M];
struct edge
{
    int y,next;
    LL f;
}e[M*2];
int last[N*2],ne=1;
int n,m;
 
void add(int x,int y,LL f)
{
    e[++ne].y=y;e[ne].f=f;e[ne].next=last[x];last[x]=ne;
}
 
void add2(int x,int y,LL f)
{
    add(x,y,f);add(y,x,0);
}
 
void init1()
{
    n=read(),m=read();
    fo(i,1,m)
    {
        int x=read(),y=read();
        LL w=read();
//      add2(x,y,w);
        ee[i].x=x;ee[i].y=y;ee[i].w=w;
        if(a[x][y]==0)
        {
            a[x][y]=w;
            a[y][x]=w;
        }
        else
        {
            a[x][y]=min(a[x][y],w);
            a[y][x]=a[x][y];
        }
    }
}
 
LL dis[N];
bitset<N>v;
void dijkstra()
{
    v.reset();
    fo(i,0,N-1)dis[i]=inf;
    dis[1]=0;
    while(1)
    {
        LL mi=inf;
        int u=0;
        fo(i,1,n)
        if(v[i]==0&&dis[i]<mi)
        {
            mi=dis[i];
            u=i;
        }
        if(u==0)return;
        v[u]=1;
        fo(i,1,n)
        if(v[i]==0&&a[u][i])
        {
            dis[i]=min(dis[u]+a[u][i],dis[i]);
        }
    }
}
 
int q[N*9];
void spfa()
{
    fo(i,0,N-1)dis[i]=inf;
    v.reset();
    int h=0,t=1;
    dis[1]=0;q[1]=1;v[1]=1;
    while(h<t)
    {
        int now=q[++h];
        efo(i,now)
        if(dis[now]+e[i].f<dis[e[i].y]&&e[i].f!=0)
        {
            dis[e[i].y]=dis[now]+e[i].f;
            if(v[e[i].y]==0)
            {
                q[++t]=e[i].y;
                v[e[i].y]=1;
            }
        }
        v[now]=0;
    }
}
 
void build()
{
    memset(last,0,sizeof(last));ne=1;
    fo(i,1,m)
    {
        int x=ee[i].x,y=ee[i].y;
        LL w=ee[i].w;
        if(dis[x]+w==dis[y])
        {
            add2(x+n,y,inf);
        }
        if(dis[y]+w==dis[x])
        {
            add2(y+n,x,inf);
        }
    }
    fo(i,1,n)
    {
        LL f=read();
        if(i!=1&&i!=n)add2(i,i+n,f);
        else add2(i,i+n,inf);
    }
}
 
int hi[N*2];
bool bfs(int s,int tt)
{
    memset(hi,0,sizeof(hi));
    int h=0,t=1;
    q[1]=s;hi[s]=1;
    while(h<t)
    {
        int now=q[++h];
        if(now==tt)return 1;
        efo(i,now)
        if(e[i].f&&hi[e[i].y]==0)
        {
            hi[e[i].y]=hi[now]+1;
            q[++t]=e[i].y;
        }
    }
    return 0;
}
 
LL dfs(int s,LL maxf,int tt)
{
    if(s==tt)return maxf;
    LL f,ret=0;
    efo(i,s)
    if(e[i].f&&hi[e[i].y]==hi[s]+1)
    {
        f=dfs(e[i].y,min(e[i].f,maxf-ret),tt);
        ret+=f;
        e[i].f-=f;
        e[i^1].f+=f;
        if(ret==maxf)return ret;
    }
    return ret;
}
 
LL dinic()
{
    LL ret=0;
    while(bfs(1,n+n))ret+=dfs(1,inf,n+n);
    return ret;
}
 
int main()
{
    memset(a,0,sizeof(a));
    init1();
//  spfa();
    dijkstra();
//  fo(i,1,n)cout<<dis[i]<<' ';cout<<endl;
    build();
    printf("%lld\n",dinic());
    return 0;
}


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