BZOJ1391【最小割】

来源：互联网发布：linux 清空日志内容编辑：程序博客网时间：2024/06/11 18:56
要加当前弧优化.
/* I will wait for you */#include<cstdio>#include<cstdlib>#include<cstring>#include<cmath>#include<ctime>#include<algorithm>#include<iostream>#include<fstream>#include<vector>#include<queue>#include<deque>#include<set>#include<map>#include<string>#define make make_pair#define fi first#define se secondusing namespace std;typedef long long LL;typedef unsigned long long ULL;typedef pair<int,int> PII;const int maxn=100010;const int maxm=1010;const int maxs=26;const int INF=1<<29;const int P=1000000007;const double error=1e-9;struct edge{ int v,a,next; }e[30*maxn];int s,t,n,m,cnt=0,ans=0,head[maxn],dis[maxn],cur[maxn],q[maxn];void addedge(int u,int v,int a){e[cnt]=(edge){v,a,head[u]},head[u]=cnt++;e[cnt]=(edge){u,0,head[v]},head[v]=cnt++;}bool bfs(){memset(dis,-1,sizeof(dis));int he=1,ta=1;dis[q[1]=s]=0;while(he<=ta){int u=q[he++];for(int i=head[u],v;i!=-1;i=e[i].next)if(e[i].a&&dis[v=e[i].v]==-1) dis[v]=dis[u]+1,q[++ta]=v;}return dis[t]!=-1;}int dfs(int u,int a){if(u==t) return a;int f,flow=0;for(int i=cur[u];a&&i!=-1;i=e[i].next){int v=e[i].v;if(e[i].a&&dis[v]==dis[u]+1&&(f=dfs(v,min(a,e[i].a)))>0){e[i].a-=f,e[i^1].a+=f,a-=f,flow+=f;if(e[i].a) cur[u]=i;}}if(!flow) dis[u]=-1;return flow;}void dinic(){while(bfs()) memcpy(cur,head,sizeof(head)),ans-=dfs(s,INF);}int main(){scanf("%d%d",&n,&m);s=n+m+1;t=n+m+2;memset(head,-1,sizeof(head));for(int i=1,w,x;i<=n;i++){ scanf("%d%d",&w,&x); addedge(s,i,w);ans+=w; for(int j=1,a,b;j<=x;j++) scanf("%d%d",&a,&b),addedge(i,n+a,b);}for(int i=1,w;i<=m;i++) scanf("%d",&w),addedge(n+i,t,w);dinic();printf("%d\n",ans);return 0;}
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