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1、Bellman-Ford
#include<iostream> #include<stdio.h> #include<vector> #include<string.h> #include<queue> using namespace std; const int maxn=1024; const int INF=0x3f3f3f3f; 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){} }; struct MCMF{ int n,m; vector<Edge>edges; vector<int>G[maxn]; int inq[maxn];//是否在队列中 int d[maxn];//Bellman-Ford int p[maxn];//上一条弧 int a[maxn];//可改进量 void init(int n){ this->n=n; 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)); m=edges.size(); G[from].push_back(m-2); G[to].push_back(m-1); } bool BellmanFord(int s,int t,int &flow,long long &cost){ for(int i=0;i<n;i++)d[i]=INF; memset(inq,0,sizeof(inq)); d[s]=0;inq[s]=1;p[s]=0;a[s]=INF; queue<int>Q; Q.push(s); while(!Q.empty()){ int u=Q.front();Q.pop(); inq[u]=0; for(int i=0;i<G[u].size();i++){ Edge &e=edges[G[u][i]]; if(e.cap>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+=(long long)d[t]*(long long)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; } //需要保证初始网络中没有负权圈 int MincostMaxflow(int s,int t,long long &cost){ int flow=0;cost=0; while(BellmanFord(s,t,flow,cost)); return flow; } }; int main(){ return 0; }
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原文地址:http://www.cnblogs.com/bofengyu/p/4989186.html