Submission #850992

#	Time	Username	Problem	Language	Result	Execution time	Memory
850992		12345678	The Big Prize (IOI17_prize)	C++17	100 / 100	32 ms	6700 KiB

prize

#include "prize.h"
#include <bits/stdc++.h>

using namespace std;

mt19937 rng(time(0));

const int nx=2e5+5;
int w, N, ans, mx,cnt, rd;
bool s;
vector<int> m[nx];

vector<int> ask2(int x)
{
	if (x<0||x>=mx) return vector<int> (2, 0);
	if (m[x].empty()) 
	{
		m[x]=ask(x);
		if (m[x][0]+m[x][1]==0) ans=x, s=1;
		return m[x];
	}
	return m[x];
}

void solve(int l, int r)
{
	if (l>r||s) return;
	if (l==r) return ask2(l), void();
	int ml=(l+r)/2, mr=(l+r)/2;
	while (ml>=l&&ask2(ml)[0]+ask2(ml)[1]!=w) ml--;
	while (mr<=r&&ask2(mr)[0]+ask2(mr)[1]!=w) mr++;
	if (ask2(ml)[0]-ask2(l-1)[0]>0) solve(l, ml-1);
	if (ask2(mr)[1]-ask2(r+1)[1]>0) solve(mr+1, r);
}

int find_best(int n) {
	mx=n;
	for (int i=0; i<=100; i++) rd=(rng()%n+n)%n, w=max(w, ask2(rd)[0]+ask2(rd)[1]);
	int l=0, r=n-1;
	//while (ask2(l)[0]+ask2(l)[1]!=w) l++;
	//while (ask2(r)[0]+ask2(r)[1]!=w) r--;
	solve(l, r);
	return ans;
}

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