求卡EK+spfa
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求卡EK+spfa
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5793__qwq楼主2023/8/4 18:51
#include<bits/stdc++.h>
#define inf 0x7f7f7f7f7f7f7f7f
#define ll long long
#define mx 5010
using namespace std;
struct edge{
	ll flow,cost,to,next;
}e[100010];
ll head[mx],flow[mx],dis[mx],pre[mx],vis[mx],mn=inf,maxf,minc,n,m,a,b,x,y,z,zz,xb=1;
queue<ll> q;
void adde(ll f,ll t,ll v,ll w){
	e[++xb].to=t;
	e[xb].flow=v;
	e[xb].cost=w;
	e[xb].next=head[f];
	head[f]=xb;
}
bool spfa(){
	while(!q.empty()) q.pop();
    memset(pre,-1,sizeof(pre));
    memset(vis,0,sizeof(vis));
    memset(dis,inf,sizeof(dis));
	q.push(a);
    flow[a]=inf;
    dis[a]=0;
    vis[a]=1;
	while(1){
		if(q.empty()==1)
            break;
		ll x=q.front();
        q.pop();
        vis[x]=0;
		for(ll i=head[x];i;i=e[i].next){
			if(e[i].flow>0&&dis[e[i].to]>dis[x]+e[i].cost){
				int t=e[i].to;
				flow[t]=min(flow[x],e[i].flow);
				dis[t]=dis[x]+e[i].cost;
				pre[t]=i;
				if(!vis[t]){
					q.push(t);
					vis[t]=1;
				}
			}
		}
	}
	if(pre[b]!=-1)
		return 1;else
		return 0;
}
void mcmf(){
	while(spfa()){
    	maxf+=flow[b];
    	minc+=dis[b]*flow[b];
		ll i=b;
		while(i!=0){
			e[pre[i]].flow-=flow[b];
			e[pre[i]^1].flow+=flow[b];
			i=e[pre[i]^1].to;
		}
	}
}
int main(){
	cin>>n>>m;
	a=1,b=n;
	for(ll i=1;i<=m;++i){
		cin>>x>>y>>z>>zz;
		adde(x,y,z,zz);
		adde(y,x,0,-zz);
	}
	mcmf();
	cout<<maxf<<' '<<minc;
	return 0;
}
2023/8/4 18:51
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