bzoj 3218: a + b Problem|最小割|主席树

本来以为是强行加主席树

没想到是主席树优化建边 太神了!!

注意主席树叶子节点的特判 wa了1h+!

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm> using namespace std;const int MAXN=5000+10;const int MAXM=5000*100;const int INF=1000000000;int tot=1,g[MAXM],nnext[MAXM],flow[MAXM],num[MAXM];void add(int x,int y,int z){tot++;nnext[tot]=g[x];g[x]=tot;num[tot]=y;flow[tot]=z;}void ADD(int x,int y,int z){add(x,y,z);add(y,x,0);}struct H{int a,b,w,l,r,p;}c[MAXN];int n,s,t,cnt;int team[MAXM],head,tail,d[MAXM];int ls[MAXN*3],id[MAXN*3]; bool bfs(){memset(d,0,sizeof(d));head=tail=0;d[s]=1;team[++tail]=s;while(head<tail){int x=team[++head];for(int i=g[x];i;i=nnext[i])if(flow[i]>0&&d[num[i]]==0){d[num[i]]=d[x]+1;team[++tail]=num[i];}}if(d[t]==0) return false;return true;}int dfs(int x,int mmin){if(x==t) return mmin;int f=0,tmp;for(int i=g[x];i;i=nnext[i])if(d[num[i]]==d[x]+1&&flow[i]>0&&(tmp=dfs(num[i],min(mmin,flow[i])))){flow[i]-=tmp;flow[i^1]+=tmp;f+=tmp;mmin-=tmp;if(mmin==0) return f;}if(f==0) d[x]=0;return f;}int find(int x){int l=1,r=3*n;while(l<r){int mid=(l+r)/2;if(ls[mid]>=x) r=mid;else l=mid+1;}return id[l];}int root[MAXN],opt;struct HH {int l,r,num;}seg[MAXM];void build(int &now,int last,int l,int r,int x){now=++opt;if(l==r) {seg[now].num=++cnt;ADD(seg[now].num,seg[last].num,INF); ADD(seg[now].num,x,INF);return ;}seg[now].num=++cnt;int mid=(l+r)/2;if(c[x].a<=mid) {seg[now].r=seg[last].r; build(seg[now].l,seg[last].l,l,mid,x);}else{seg[now].l=seg[last].l; build(seg[now].r,seg[last].r,mid+1,r,x);}if(seg[now].l!=0) ADD(seg[now].num,seg[seg[now].l].num,INF);if(seg[now].r!=0) ADD(seg[now].num,seg[seg[now].r].num,INF);}void link(int now,int l,int r,int s,int t,int i){if(now==0) return ;if(s<=l&&r<=t){ADD(i,seg[now].num,INF);return ;}int mid=(l+r)/2;if(s<=mid) link(seg[now].l,l,mid,s,t,i);if(mid+1<=t) link(seg[now].r,mid+1,r,s,t,i);}int main(){scanf("%d",&n);cnt=2*n;s=++cnt,t=++cnt;int ans=0;for(int i=1;i<=n;i++) scanf("%d %d %d %d %d %d",&c[i].a,&c[i].b,&c[i].w,&c[i].l,&c[i].r,&c[i].p),ans+=c[i].w+c[i].b,ls[i]=c[i].l,ls[i+n]=c[i].r,ls[i+n*2]=c[i].a;for(int i=1;i<=n;i++) ADD(i,i+n,c[i].p),ADD(s,i,c[i].b),ADD(i,t,c[i].w);sort(ls+1,ls+3*n+1);id[1]=1;for(int i=2;i<=3*n;i++) if(ls[i]!=ls[i-1]) id[i]=id[i-1]+1; else id[i]=id[i-1];for(int i=1;i<=n;i++) c[i].l=find(c[i].l),c[i].r=find(c[i].r),c[i].a=find(c[i].a);for(int i=1;i<=n;i++) link(root[i-1],1,id[3*n],c[i].l,c[i].r,i+n),build(root[i],root[i-1],1,id[3*n],i);while(bfs()) ans-=dfs(s,INF);printf("%d\n",ans);return 0;}