Power Network POJ

http://poj.org/problem?id=1459

嗯,网络流模板...多源点多汇点的图,超级汇点连发电厂,用户连接超级汇点

Status	Accepted
Time	391ms
Memory	1588kB
Length	2166
Lang	G++
Submitted	2018-05-23 14:43:22
Shared
RemoteRunId	18625420

#include <iostream>
#include <string.h>
#include <cmath>
#define ll long long
#define IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define pp pair<int,int>
#define rep(ii,a,b) for(int ii=a;ii<=b;ii++)
#define	per(ii,a,b) for(int ii=a;ii>=b;ii--)
#define show(x) cout<<#x<<"="<<x<<endl
#define show2(x,y) cout<<#x<<"="<<x<<" "<<#y<<"="<<y<<endl
#define show3(x,y,z) cout<<#x<<"="<<x<<" "<<#y<<"="<<y<<" "<<#z<<"="<<z<<endl
#define showa(a,b) cout<<#a<<'['<<b<<"]="<<b[a]<<endl
using namespace std;
const int maxn=1e5+10;
const int maxm=1e6+10;
const ll INF=0x3f3f3f3f3f;
int casn,n,np,nc,m,k;
struct node {int to;ll cap;int next;}e[maxm];
int ss,tt,head[maxn],nume,dis[maxn],q[maxn];
inline void addx(int a,int b,ll c){
	e[++nume]=(node){b,c,head[a]};
	head[a]=nume;
}
inline void add(int a,int b,ll c){
	addx(a,b,c);addx(b,a,0);
}
bool bfs(int s=ss,int t=tt){
	int top=0,end=1;
	q[0]=s;
	for(int i=0;i<=t;i++) dis[i]=0;
	dis[s]=1;
	while(top!=end){
		int now=q[top++];top%=maxn;
		for(int i=head[now];i;i=e[i].next){
			int to=e[i].to;
			if(!dis[to]&&e[i].cap){
				dis[to]=dis[now]+1;
				if(to==t)break;
				q[end++]=to;end%=maxn;
			}
		}
	}
	return dis[t];
}
ll dfs(int now=ss,ll last=INF){
	if(now==tt)return last;
	ll flow=0,det;
	for(int i=head[now];i;i=e[i].next){
		int to=e[i].to;
		if(e[i].cap&&dis[to]==dis[now]+1){
			det=dfs(to,min(last-flow,e[i].cap));
			flow+=det;
			e[i].cap-=det;
			e[i^1].cap+=det;
			if(flow==last) return last;
		}
	}
	if(flow==0) dis[now]=-1;
	return flow;
}


int main(){
//#define test
#ifdef test
	freopen("in.txt","r",stdin);freopen("out.txt","w",stdout);
#endif
	int nc,np;
	IO;
	while(cin>>n>>np>>nc>>m){
		char ch;
		memset(head,0,sizeof head);
		nume=1;
		ss=n+9,tt=n+10;
		rep(i,1,m) {
			int a,b,c;
			cin>>ch>>a>>ch>>b>>ch>>c;
			if(a==b) continue;
			add(a,b,c);
		}
		rep(i,1,np){
      int a,b,c;
      cin>>ch>>a>>ch>>c;
      add(ss,a,c);
		}
		rep(i,1,nc){
			int a,b,c;
			cin>>ch>>a>>ch>>c;
			add(a,tt,c);
		}
		int ans=0;
		while(bfs()){
//      show(1);
			ans+=dfs();
//			show(ans);

		}
		cout<<ans<<'
';
	}
#ifdef test
	fclose(stdin);fclose(stdout);system("out.txt");
#endif
	return 0;
}