最小费用最大流模板

来源：互联网发布：网络用语xjbs什么意思编辑：程序博客网时间：2024/06/14 07:53
#include<iostream>#include<cstdio>#include<cstring>#include<cmath>#include<algorithm>#include<map>#include<set>#include<queue>#include<stack>#include<vector>using namespace std;typedef long long ll;#define mem(name,value) memset(name,value,sizeof(name))#define lson l,m,rt<<1#define rson m+1,r,rt<<1|1const int maxn=210,maxm=110*110,inf=0x3f3f3f3f;struct Side{    int from,to,next,cap,flow,cost;};struct MCMF{    int n,top;    Side side[maxm*2];    int node[maxn],inq[maxn],d[maxn],pre[maxn],a[maxn];    void init(){         top=0; mem(node,-1);    }    void add_side(int u,int v,int cap,int cost){        side[top]=(Side){u,v,node[u],cap,0,cost};        node[u]=top++;        side[top]=(Side){v,u,node[v],0,0,-cost};        node[v]=top++;    }    bool SPFA(int s,int t,int &flow,int &cost){        //for(int i=0;i<=n;i++) d[i]=inf;        mem(d,inf);        //cout<<d[0]<<endl;        mem(inq,0);        d[s]=0; inq[s]=1; pre[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=node[u];i!=-1;i=side[i].next){                int v=side[i].to;                if(side[i].cap>side[i].flow && d[v]>d[u]+side[i].cost){                    d[v]=d[u]+side[i].cost;                    pre[v]=i;                    a[v]=min(a[u],side[i].cap-side[i].flow);                    if(!inq[v]){ q.push(v); inq[v]=1;}                }            }        }        if(d[t]==inf) return 0;        flow+=a[t]; cost+=a[t]*d[t];        int u=t;        while(u!=s){            side[pre[u]].flow+=a[t];            side[pre[u]^1].flow-=a[t];            u=side[pre[u]].from;        }        return true;    }    int get_mincost(int s,int t){        int flow=0,cost=0;        while(SPFA(s,t,flow,cost));        return cost;    }}mcmf;int n,m;char maze[maxn][maxn];struct Node{    int x,y;};vector<Node>H,M;int main(){    while(cin>>n>>m && n+m){        for(int i=0;i<n;i++) scanf("%s",&maze[i]);        H.clear(); M.clear();        for(int i=0;i<n;i++)            for(int j=0;j<m;j++){                if(maze[i][j]=='H') H.push_back((Node){i,j});                else if(maze[i][j]=='m') M.push_back((Node){i,j});            }        int nn=H.size();        mcmf.init();        for(int i=0;i<nn;i++)            for(int j=0;j<nn;j++){                int dist=abs(H[i].x-M[j].x)+abs(H[i].y-M[j].y);                mcmf.add_side(i+1,nn+j+1,1,dist);            }        for(int i=0;i<nn;i++) mcmf.add_side(0,i+1,1,0);        for(int i=0;i<nn;i++) mcmf.add_side(nn+i+1,nn+nn+1,1,0);        int ans=mcmf.get_mincost(0,nn+nn+1);        printf("%d\n",ans);    }}
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