Submission #524855

#	Time	Username	Problem	Language	Result	Execution time	Memory
524855		CSQ31	The Big Prize (IOI17_prize)	C++17	100 / 100	62 ms	6008 KiB

prize

#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
int num = 0;
#define sz(a) (int)(a.size());
vector<int>res[200000];
int cnt = 0;
int solve(int l,int r,int lf = 0,int rg = 0){
	if(l > r)return -1;
	int mid = (l+r)/2;
	for(int i=0;i<=r-l;i++){
		int ml = mid-i/2;
		int mr = mid+(i+1)/2;
		int m = i%2==0?ml : mr;
		int tmpl = i%2==0?0:mr-ml;
		int tmpr = i%2==1?0:mr-ml;
		res[m] = ask(m);
		if(!res[m][0] && !res[m][1])return m;
		if(res[m][0] + res[m][1] == num){
			int c = -1;
		     if(res[m][0]-tmpl>lf)c = max(c,solve(l,ml-1,lf,res[m][1]+tmpl));
	         if(res[m][1]-tmpr>rg)c = max(c,solve(mr+1,r,res[m][0]+tmpr,rg));
	         return c;
	         
		}
	}
	return -1;
		
}
int find_best(int n) {
	vector<int>a(n);
	for(int i=0;i<n;i++)a[i] = i;
	int p = 0;
	for(int i=0;i<min(n,(int)(sqrt(n)+30)) && num < 27;i++){
		vector<int>res = ask(i);
		if(!res[0] && !res[1])return i;
		if(res[0] + res[1] > num){
			num = res[0] + res[1];
			p = i;
		}
	}
	
	//d&c to try all small guys since < #small guys < sqrt(n)
	return solve(p,n-1,p,0);
}

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