Submission #966340

#	Time	Username	Problem	Language	Result	Execution time	Memory
966340		bachhoangxuan	The Big Prize (IOI17_prize)	C++17	20 / 100	54 ms	7208 KiB

prize

#include "prize.h"
#include<bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int B = 500;
const int maxn = 2e5+5;

vector<int> res[maxn];
vector<int> get(int x){
    if(!res[x].empty()) return res[x];
    res[x]=ask(x);res[x][1]+=res[x][0];
    return res[x];
}

int N,bit[maxn],Max;
void update(int x){
    for(int i=x+1;i<=N;i+=(i&(-i))) bit[i]++;
}
int query(int x){
    int ans=0;
    for(int i=x+1;i>=1;i-=(i&(-i))) ans+=bit[i];
    return ans;
}

int find_best(int n){
    N=n;
    vector<int> ord(min(n,500));
    iota(ord.begin(),ord.end(),0);
    shuffle(ord.begin(),ord.end(),rng);
    for(int i=0;i<400;i++){
        vector<int> cc=get(ord[i]);
        if(cc[1]==0) return ord[i];
        Max=max(Max,cc[1]);
    }
    for(int i=0;i<n;i+=B){
        vector<int> p;
        for(int j=i;j<min(i+B,n);j++) p.push_back(j);
        int cnt=0;
        while(!p.empty()){
            int x=p.back();p.pop_back();
            vector<int> cc=get(x);
            if(cc[1]==0) return x;
            if(cc[1]<Max) update(x);
            else{
                cnt=cc[0]-query(x);
                break;
            }
        }
        while(cnt){
            int l=0,r=(int)p.size()-1;
            while(l<=r){
                int mid=(l+r)>>1;
                vector<int> cc=get(p[mid]);
                if(cc[1]==0) return p[mid];
                if(cc[1]<Max){
                    update(p[mid]);
                    p.erase(p.begin()+mid);
                    break;
                }
                if(cc[0]-query(p[mid])) r=mid-1;
                else l=mid+1;
            }
            cnt--;
        }
    }
	return -1;
}

• Subtask 1: 20 / 20
• Subtask 2: 0 / 80