BZOJ 1834 网络扩容

第一问求最大流，第二问求最小费用最大流。

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#define LL long long
using namespace std;
const int maxn = 1000000 + 10;
const int INF = 10000000;
struct Edge
{int from,to,cap,flow,cost;Edge(int u,int v,int c,int f,int w):from(u),to(v),cap(c),flow(f),cost(w) { }
};
int n , m;
vectoredges;
vectorG[maxn];
int inq[maxn];
int d[maxn];
int p[maxn];
int a[maxn];
void init()
{for(int i=0;i<=n;i++)G[i].clear();edges.clear();
}
void AddEdge(int from,int to,int cap,int cost)
{edges.push_back(Edge(from,to,cap,0,cost));edges.push_back(Edge(to,from,0,0,-cost));int M = edges.size();G[from].push_back(M-2);G[to].push_back(M-1);
}
bool SPFA(int s,int t,int& flow,LL& cost)
{for(int i=0;i<=n+1;i++)d[i] = INF;memset(inq,0,sizeof(inq));d[s] = 0;inq[s] = 1;p[s] = 0;a[s] = INF;queueQ;Q.push(s);while(!Q.empty()){int u = Q.front();Q.pop();inq[u] = 0;for(int i=0;i e.flow && d[e.to] > d[u] + e.cost){d[e.to] = d[u] + e.cost;p[e.to] = G[u][i];a[e.to] = min(a[u],e.cap-e.flow);if(!inq[e.to]) {Q.push(e.to);inq[e.to] = 1;}}}}if(d[t] == INF) return false;flow += a[t];cost += (LL)d[t] * (LL)a[t];for(int u=t;u!=s;u=edges[p[u]].from){edges[p[u]].flow += a[t];edges[p[u]^1].flow -= a[t];}return true;
}
int MincostMaxflow(int s,int t,LL &cost)
{int flow = 0;cost = 0;while(SPFA(s,t,flow,cost));return flow;
}
struct Node
{int u,v,c,w;
}node[maxn];
int k;
int main()
{while(scanf("%d%d%d",&n,&m,&k)!=EOF){int u,v,c,w;for(int i=1;i<=m;i++){scanf("%d%d%d%d",&node[i].u,&node[i].v,&node[i].c,&node[i].w);}for(int i=1;i<=m;i++)AddEdge(node[i].u,node[i].v,node[i].c,0);LL cost = 0;int Maxflow = MincostMaxflow(1,n,cost);AddEdge(0,1,k,0);AddEdge(n,n+1,k,0);for(int i=1;i<=m;i++){AddEdge(node[i].u,node[i].v,INF,node[i].w);AddEdge(node[i].u,node[i].v,0,-node[i].w);}MincostMaxflow(0,n+1,cost);printf("%d %d\n",Maxflow,cost);}return 0;
}

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