Submission #1163856

#	Time	Username	Problem	Language	Result	Execution time	Memory
1163856		cnn008	The Big Prize (IOI17_prize)	C++20	20 / 100	24 ms	1976 KiB

prize

#include "prize.h"
#include "bits/stdc++.h"
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r){
    assert(l<=r);
    return uniform_int_distribution<int> (l,r)(rng);
}
pair <int,int> mp[200005];
pair <int,int> get(int i){
	if(mp[i].first || mp[i].second) return mp[i];
	auto vi=ask(i);
	pair <int,int> ans={vi[0],vi[1]};
	return mp[i]=ans;
}
int find_best(int n) {
	int mx=0;
	for(int i=1; i<=20; i++){
		int k=rand(0,n-1);
		if(i==1) k=1;
		auto [u,v]=get(k);
		if(!u and !v) return k;
		mx=max(mx,u+v);
	}
	bool ok=(n-mx>=200);
	int L=0,R=n-1,kep=0;
	for(int _=0; _<=1000; _++){
		while(1){
			auto [u,v]=get(L);
			if(!u and !v) return L;
			if(u+v==mx){
				kep=u;
				break;
			}else L++;
		}
		int l=L,r=R,ans=-1;
		// cerr<<_<<" "<<kep<<endl;
		// cerr<<"range : "<<L<<" "<<R<<endl;
		while(l<=r){
			int mid=(l+r)>>1;
			auto [u,v]=get(mid);
			if(!u and !v) return mid;
			// cerr<<"db : "<<l<<" "<<r<<endl;
			// cerr<<mid<<" "<<u<<" "<<v<<endl;
			if(!u){
				ans=max(ans,mid+1);
				if(u+v==mx) l=mid+1;
				else break;
			}else{
				if(u+v==1){
					r=mid-1;
					R=min(R,mid-1);
				}else if(u+v!=mx){
					if(ok and r-l<=100) ans=max(ans,mid+1);
					r=mid-1;
				}else{
					if(u<=kep) l=mid+1;
					else r=mid-(u-kep);
				}
			}
		}
		L=max(L+1,ans);
	}
	assert(0);
	return 0;
}

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