Submission #790782

#	Time	Username	Problem	Language	Result	Execution time	Memory
790782		ttamx	The Big Prize (IOI17_prize)	C++14	20 / 100	89 ms	10588 KiB

prize

#include "prize.h"
#include<bits/stdc++.h>
 
using namespace std;
 
mt19937 rng(time(nullptr));
 
const int N=2e5+5;
 
int cnt=0;
int n;
int ans=-1;
vector<vector<int>> mem(N);
int mx;
int le,ri;
 
vector<int> ask2(int x){
	if(mem[x].empty()){
		assert(++cnt<=1e4);
		mem[x]=ask(x);
	}
	return mem[x];
}
 
void bsearch(int l,int r){
	int m=(l+r)/2;
	int idx=m;
	auto res=ask2(idx);
	int val=res[0]+res[1];
	if(val==0)ans=idx;
	if(l==r)return;
	while(val<mx&&idx+1<=r){
		idx++;
		res=ask2(idx);
		val=res[0]+res[1];
		if(val==0)ans=idx;
	}
	if(val==mx){
		if(res[0]-le){
			if(l<=m-1){
				ri+=res[1];
				bsearch(l,m-1);
				ri-=res[1];
			}
		}
		if(res[1]-ri){
			if(idx+1<=r){
				le+=res[0];
				bsearch(idx+1,r);
				le-=res[0];
			}
		}
	}else{
		idx=m-1;
		res=ask2(idx);
		val=res[0]+res[1];
		if(val==0)ans=idx;
		while(val<mx&&idx-1>=l){
			idx--;
			res=ask2(idx);
			val=res[0]+res[1];
			if(val==0)ans=idx;
		}
		if(val==mx){
			if(res[0]-le){
				if(l<=idx-1){
					ri+=res[1];
					bsearch(l,idx-1);
					ri-=res[1];
				}
			}
		}
	}
}
 
int find_best(int _n) {
	n=_n;
	for(int i=0;i*i<=n;i++){
		auto res=ask2(i);
		mx=max(mx,res[0]+res[1]);
	}
	for(int i=0;i*i<n;i++){
		auto res=ask2(i);
		if(res[0]+res[1]==mx)continue;
		if(res[0]+res[1]==0)return i;
	}
	bsearch(0,n-1);
	return ans;
}

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