ZOJ 2314 Reactor Cooling

来源：互联网发布：linux c 网络库编辑：程序博客网时间：2024/05/22 05:20
无源无汇上下界网络流裸题
#include <cstdio>#include <iostream>#include <algorithm>#include <cstring>#include <cmath>#include <queue>#include <vector>using namespace std;#define N 210#define INF 1000000000int n,m,S,T,Ans;struct Edge{    int to,next;    int value;}edge[N*N*2];int head[N],tot=1;int dis[N],cur[N],Free[N],low[N*N];queue<int> Q;inline int read(){    int x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}    while(ch<='9'&&ch>='0'){x=x*10+ch-'0';ch=getchar();}    return x*f;}void Addedge(int u,int v,int w){    tot++;edge[tot].next=head[u];edge[tot].value=w;edge[tot].to=v;head[u]=tot;    tot++;edge[tot].next=head[v];edge[tot].value=0;edge[tot].to=u;head[v]=tot;}bool BFS(){    memset(dis,-1,sizeof(dis));    dis[S]=0;Q.push(S);    while(!Q.empty())    {        int now=Q.front();Q.pop();        for(int i=head[now];i;i=edge[i].next)        {            int v=edge[i].to;            if(dis[v]<0&&edge[i].value>0)            {                dis[v]=dis[now]+1;                Q.push(v);            }        }    }    return dis[T]>0;}int Find(int k,int low){    if(k==T)        return low;    int qwer;    for(int i=cur[k];i;i=edge[i].next)    {        cur[k]=i;        int v=edge[i].to;        if(dis[v]==dis[k]+1&&edge[i].value>0&&(qwer=Find(v,min(low,edge[i].value))))        {            edge[i].value-=qwer;            edge[i^1].value+=qwer;            return qwer;        }    }    return 0;}void Dinic(){    while(BFS())    {        for(int i=0;i<=T;i++)            cur[i]=head[i];        while(1)        {            int qwer=Find(S,INF);            if(qwer==0)                break;            Ans+=qwer;        }    }}bool Pd(){    for(int i=head[S];i;i=edge[i].next)    {        if(edge[i].value)            return false;    }    return true;}int main(){    int Case=read();    while(Case--)    {        tot=1;        memset(head,0,sizeof(head));        memset(Free,0,sizeof(Free));        n=read();m=read();        S=0;T=n+1;        for(int i=1;i<=m;i++)        {            int x=read(),y=read();low[i]=read();int z=read();            Free[x]-=low[i];Free[y]+=low[i];            Addedge(x,y,z-low[i]);        }        for(int i=1;i<=n;i++)        {            if(Free[i]>0)                Addedge(S,i,Free[i]);            else Addedge(i,T,-Free[i]);        }        Ans=0;Dinic();        if(Pd())        {            printf("YES\n");            for(int i=1;i<=m;i++)            {                printf("%d\n",edge[i*2+1].value+low[i]);            }        }        else printf("NO\n");    }    return 0;}
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