CTSC2018 混合果汁

Posted 2022-12-15 yzhx

传送门

题解

先把 \(d\) 二分,然后按价格插入主席树,主席树中维护当前区间水果的重量和与总价值,大概就是这样子.

#include<bits/stdc++.h>
using namespace std;
#define re register
#define int long long
#define in inline
#define get getchar()
in int read()

    int t=0,x=1; char ch=get;
    while((ch<'0' || ch>'9') && ch!='-') ch=get;
    if(ch=='-') ch=get,x=-1;
    while(ch<='9' && ch>='0') t=t*10+ch-'0', ch=get;
    return t*x;

const int _=1e5+6;
struct juice
    int d,p,l;
bool operator < (const juice& other)const        
     
         return d < other.d;
     
a[_];
int sumc[_<<6],suml[_<<6],ls[_<<6],rs[_<<6],tot,n,m,G,L,root[_];

in void add(int k,int &now, int l,int r,int p,int v)

    now=++tot;
    ls[now]=ls[k],rs[now]=rs[k],sumc[now]=sumc[k]+p*v,suml[now]=suml[k]+v;
    if(l==r)
        return;
    int mid=l+r>>1;
    if(p<=mid) add(ls[k],ls[now],l,mid,p,v);
    else add(rs[k],rs[now],mid+1,r,p,v);
    return;

in int query(int k1,int k2,int l,int r,int x)

    if(l==r) return min(x/l, suml[k2]-suml[k1]);
    int s=sumc[ls[k2]]-sumc[ls[k1]],mid=l+r>>1;
    if(x<=s) return query(ls[k1],ls[k2],l,mid,x);
    else return suml[ls[k2]]-suml[ls[k1]]+query(rs[k1],rs[k2],mid+1,r,x-s);

in bool check(int i)

    int qwe=query(root[i-1],root[n],1,_-6,G);
//  cout<<qwe<<endl;
    return qwe>=L;

in int getans()


    int l=0,r=n;
    while(l<r)
    
        int mid=l+r+1>>1;
        if(check(mid)) l=mid;
        else r=mid-1;
    
    return !l ? -1 :a[l].d;

signed main()

    n=read(),m=read();
    for(re int i=1;i<=n;i++)
        a[i].d=read(),a[i].p=read(),a[i].l=read();
    sort(a+1,a+n+1);
    for( int i=1;i<=n;i++) add(root[i-1],root[i],1,_-6,a[i].p,a[i].l);
    for(re int i=1;i<=m;i++)
    
        G=read(),L=read();
        printf("%lld\n",getans());
    
    return 0;