poj 2010 Moo University

poj 2010 Moo University

#include <iostream>#include <cmath>#include <cstdio>#include <algorithm>#define lson step<<1#define rson step<<1|1#define LL long longusing namespace std;const int N = 100005;struct Node{int cost,val;bool operator<(const Node n)const{return val<n.val;}}a[N];struct Seg_tree{int left,right;int small,large;}L[N<<2];int m,n,f,x[N],tot;LL Left=0,Right=0;void bulid(int step,int l,int r){L[step].left=l;L[step].right=r;L[step].small=L[step].large=0;if(l==r) return ;int m=(l+r)>>1;bulid(lson,l,m);bulid(rson,m+1,r);}void insert(int step,int pos,int kind){if(!kind) L[step].small++;else L[step].large++;if(L[step].left==pos&&pos==L[step].right) return ;int m=(L[step].left+L[step].right)>>1;if(pos<=m) insert(lson,pos,kind);else insert(rson,pos,kind);}int query(int step,int k,int kind){if(L[step].left==L[step].right) return L[step].left;int m=(L[step].left+L[step].right)>>1;if(!kind){if(L[lson].small>=k) return query(lson,k,kind);else return query(rson,k-L[lson].small,kind);}else{if(L[lson].large>=k) return query(lson,k,kind);else return query(rson,k-L[lson].large,kind);}}void remove(int step,int pos,int kind){if(!kind) L[step].small--;else L[step].large--;if(L[step].left==L[step].right) return ;int m=(L[step].left+L[step].right)>>1;if(pos<=m) remove(lson,pos,kind);else remove(rson,pos,kind);}int main(){scanf("%d%d%d",&m,&n,&f);for(int i=0;i<n;i++){scanf("%d%d",&a[i].val,&a[i].cost);x[i]=a[i].cost;}sort(a,a+n);sort(x,x+n);tot=unique(x,x+n)-x;bulid(1,1,tot);for(int i=0;i<m/2;i++){Left+=(LL)a[i].cost;int pos=lower_bound(x,x+tot,a[i].cost)-x+1;insert(1,pos,0);}for(int i=m/2+1;i<n;i++){int pos=lower_bound(x,x+tot,a[i].cost)-x+1;if(i<m){Right+=(LL)a[i].cost;insert(1,pos,1);}else{int idx=query(1,m/2,1);if(a[i].cost<x[idx-1]) Right=Right-x[idx-1]+a[i].cost;insert(1,pos,1);}}int ans=-1;for(int i=m/2;i<n-m/2;i++){if((LL)Left+Right+a[i].cost<=f){ans=max(ans,a[i].val);}int pos=lower_bound(x,x+tot,a[i].cost)-x+1;int idx=query(1,m/2,0);if(a[i].cost<x[idx-1]){Left-=(LL)x[idx-1];Left+=(LL)a[i].cost;remove(1,idx,0);insert(1,pos,0);}pos=lower_bound(x,x+tot,a[i+1].cost)-x+1;remove(1,pos,1);idx=query(1,m/2,1);if(a[i+1].cost<x[idx-1]){Right-=(LL)a[i+1].cost;Right+=(LL)x[idx-1];}}printf("%dn",ans);    return 0;}