求助!费用流TLE63分
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求助!费用流TLE63分
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羊叫兽同学楼主2022/7/20 21:05
#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
const int aaa=114514;
int n,m,s,l,t,ans_flow,ans_cost,qwq,top=1,u[aaa],v[aaa],flow[aaa],cost[aaa],first[aaa],nxt[aaa],dis[aaa],second[aaa],a,b,c,d,sum;
bool book[aaa];
queue<int>q;
void add(int a,int b,int c,int d)
{
	top++;
	u[top]=a;
	v[top]=b;
	flow[top]=c;
	cost[top]=d;
	nxt[top]=first[a];
	first[a]=top;
	top++;
	u[top]=b;
	v[top]=a;
	flow[top]=0;
	cost[top]=-d;
	nxt[top]=first[b];
	first[b]=top;
}
bool spfa()
{
	int x,i;
	while(!q.empty())
		q.pop();
	for(i=1;i<=n;i++)
		dis[i]=0x3f3f3f3f;
	memset(book,0,sizeof(book));
	dis[s]=0;
	book[s]=true;
	q.push(s);
	while(!q.empty())
	{
		x=q.front();
		q.pop();
		for(i=first[x];i!=0;i=nxt[i])
		{
			if(flow[i]!=0&&dis[x]+cost[i]<dis[v[i]])
			{
				dis[v[i]]=dis[x]+cost[i];
				if(!book[v[i]])
				{
					book[v[i]]=1;
					q.push(v[i]);
				}
			}
		}
	}
	if(dis[t]==0x3f3f3f3f)
		return false;
	return true;
}
int dfs(int x,int maxflow)
{
	if(x==t)
		return maxflow;
	book[x]=true;
	int i,sum=0,mi;
	for(i=second[x];i!=0;i=nxt[i])
	{
		second[x]=i;
		if(dis[x]+cost[i]==dis[v[i]]&&flow[i]!=0&&book[v[i]]==false)
		{
			mi=dfs(v[i],min(maxflow-sum,flow[i]));
			if(mi!=0)
			{
				flow[i]-=mi;
				flow[i^1]+=mi;
				sum+=mi;
				ans_cost+=cost[i]*mi;
				if(sum==maxflow)
					break;
			}
		}
	}
	book[x]=false;
	if(sum==0)
		dis[x]=0x3f3f3f3f;
	return sum;
}
int main()
{
	int i;
	scanf("%d%d%d%d",&n,&m,&s,&t);
	for(i=1;i<=m;i++)
	{
		scanf("%d%d%d%d",&a,&b,&c,&d);
		add(a,b,c,d);
	}
	while(spfa())
	{
		memset(book,0,sizeof(book));
		memcpy(second,first,sizeof(first));
		ans_flow+=dfs(s,0x3f3f3f3f);
	}
	printf("%d %d",ans_flow,ans_cost);
	return 0;
}
2022/7/20 21:05
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