MLE on #8~#11 63pts Dinic+spfa 求调
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MLE on #8~#11 63pts Dinic+spfa 求调
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lunjiahao楼主2024/7/19 11:32
#include<bits/stdc++.h>
using namespace std;
const int N=5e3+5,M=5e4+5,INF=0x3f3f3f3f;
int n,m,s,t,maxflow,mincost;
int cnt=1,head[N],cur[N],dis[N];
bool vis[N];
struct Edge
{
	int v,nxt,w,c;
}e[M<<1];
void add(int u,int v,int w,int c)
{
	e[++cnt].v=v;
	e[cnt].w=w;
	e[cnt].c=c;
	e[cnt].nxt=head[u];
	head[u]=cnt;
}
bool bfs()
{
	memset(vis,false,sizeof(vis));
	memset(dis,0x3f,sizeof(dis));
	dis[s]=0;
	queue<int> q;
	q.push(s);
	while(!q.empty())
	{
		int u=q.front();
		q.pop();
		for(int i=head[u];i;i=e[i].nxt)
		{
			int v=e[i].v;
			if(e[i].w&&dis[u]+e[i].c<dis[v])
			{
				dis[v]=dis[u]+e[i].c;
				if(!vis[v]) vis[v]=1,q.push(v);
			}
		}
		vis[u]=0;
	}
	return dis[t]^INF;
}
int dfs(int u,int flow)
{
	if(u==t||!flow) return flow;
	int used=0;
	vis[u]=1;
	for(int i=cur[u];i&&flow;i=e[i].nxt)
	{
		cur[u]=i;
		int v=e[i].v,tmp=dfs(v,min(e[i].w,flow));
		if(!vis[v]&&e[i].w&&dis[v]==dis[u]+e[i].c&&tmp>0)
		{
			mincost+=tmp*e[i].c;
			e[i].w-=tmp,e[i^1].w+=tmp;
			used+=tmp,flow-=tmp;
		}
	}
	vis[u]=0;
	if(!used) dis[u]=INF;
	return used;
}
void Dinic()
{
	while(bfs())
	{
		memcpy(cur,head,sizeof(head));
		maxflow+=dfs(s,INF);
	}
}
int main()
{
	scanf("%d%d%d%d",&n,&m,&s,&t);
	for(int i=1;i<=m;i++)
	{
		int u,v,w,c;
		scanf("%d%d%d%d",&u,&v,&w,&c);
		add(u,v,w,c),add(v,u,0,-c);
	}
	Dinic();
	printf("%d %d",maxflow,mincost);
	return 0;
}

似乎是爆栈了()

2024/7/19 11:32
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