Submission #1205274

#	Time	Username	Problem	Language	Result	Execution time	Memory
1205274		shadowcoder	The Big Prize (IOI17_prize)	C++20	90 / 100	21 ms	2172 KiB

prize

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

using namespace std;

const int maxn = 200005;

bool asked[maxn];
int ansL[maxn], ansR[maxn];

void query(int pos)
{
	if (asked[pos] == true) return;
	asked[pos] = true;
	vector<int> curr = ask(pos);
	ansL[pos] = curr[0];
	ansR[pos] = curr[1];
}

const int SEARCH_TO = 500;

int find_best(int n)
{
	/*if (n <= 5000)
	{
		for (int i = 0; i < n; ++i)
		{
			query(i);
			if (ansL[i] + ansR[i] == 0) return i;
		}
	}*/

	for (int i = 0; i < SEARCH_TO; ++i)
	{
		query(i);
		if (ansL[i] + ansR[i] == 0) return i;
	}

	int start = 0, better = 0;
	int maxSum = ansL[0] + ansR[0];

	for (int i = 1; i < SEARCH_TO; ++i)
	{
		if (ansL[start] + ansR[start] < ansL[i] + ansR[i])
		{
			start = i;
			maxSum = ansL[i] + ansR[i];
		}
	}

	for (int i = 0; i < start; ++i)
	{
		if (ansL[i] + ansR[i] < ansL[start] + ansR[start])
		{
			++better;
		}
	}

	while (true)
	{
		//cout << start << " :: " << better << endl;
		int l = start + 1;
		int r = n - 1;

		while (l <= r)
		{
			int mid = (l + r) / 2;
			query(mid);

			//cout << l << " " << r << " " << mid << " :: " << ansL[mid] << " " << ansR[mid] << endl;

			if (ansL[mid] + ansR[mid] == 0) return mid;

			if (ansL[mid] + ansR[mid] < maxSum)
			{
				r = mid - 1;
			}
			else
			{
				if (ansL[mid] > better) r = mid - 1;
				else l = mid + 1;
			}
		}

		int blockEnd = r;
		//cout << "now " << blockEnd << endl;

		for (int i = blockEnd + 1; i < n; ++i)
		{
			query(i);
			if (ansL[i] + ansR[i] == 0) return i;
			if (ansL[i] + ansR[i] == maxSum)
			{
				start = i;
				break;
			}
			++better;
		}
	}
}

• Subtask 1: 20 / 20
• Subtask 2: 70 / 80