Submission #69475

#	Time	Username	Problem	Language	Result	Execution time	Memory
69475		Diuven	The Big Prize (IOI17_prize)	C++14	20 / 100	54 ms	2376 KiB

prize

#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
typedef vector<int> vi;
const int MX=200010;

bool up[MX];
int L[MX], R[MX], sum, n, ans;

void my_ask(int i){
	static set<int> S;
	if(S.find(i)!=S.end()) return;
	S.insert(i);
	vi now=ask(i);
	L[i]=now[0], R[i]=now[1];
}

void search(int s, int e, int lc, int mc, int rc){
	if(s>e || mc==0) return;
	assert(mc>=0);

	int m=(s+e)/2;

	for(int i=m; i<=e; i++){
		my_ask(i);
		if(L[i]+R[i]==0){ ans=i; return; }
		if(L[i]+R[i]==sum){
			search(s,m-1, lc, L[i]-(i-m)-lc, R[i]+i-m);
			search(i+1,e, L[i], R[i]-rc, rc);
			return;
		}
	}
	for(int i=m; i>=s; i--){
		my_ask(i);
		if(L[i]+R[i]==0){ ans=i; return; }
		if(L[i]+R[i]==sum){
			search(s,i-1, lc, L[i]-lc, R[i]);
			return;
		}
	}
}

void get(){
	srand(time(NULL));
	for(int i=0; i<20; i++){
		int x=rand()%n; my_ask(x);
		sum=max(sum, L[x]+R[x]);
	}
}

int find_best(int _n){
	n=_n;
	get();
	ans=-1;
	search(0,n-1,0,sum,0);
	assert(ans>=0);
	return ans;
}

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