Submission #1256089

#	Time	Username	Problem	Language	Result	Execution time	Memory
1256089		gelastropod	The Big Prize (IOI17_prize)	C++20	100 / 100	12 ms	1944 KiB

prize

#include "prize.h"
#include <bits/stdc++.h>
using namespace std;

int ans = -1, lolpop = 0;
vector<pair<int, int>> cache;

pair<int, int> qry(int i) {
	if (cache[i].first == -1) {
		auto j = ask(i);
		cache[i] = {j[0], j[1]};
		if (j[0] + j[1] == 0) ans = i;
	}
	return cache[i];
}

void dnc(int l, int r, int numl, int numr) {
	int m = (l + r) / 2;
	for (int i = 0; i <= r - l; i++) {
		int lbound = m - i / 2, rbound = m + (i + 1) / 2, truem = (i % 2 ? rbound : lbound);
		auto j = qry(truem);
		if (ans != -1) return;
		if (j.first + j.second == lolpop) {
			if (i % 2) {
				if (j.second > numr) dnc(rbound + 1, r, j.first, numr);
				if (j.first - i > numl) dnc(l, lbound - 1, numl, j.second + i);
			}
			else {
				if (j.first > numl) dnc(l, lbound - 1, numl, j.second);
				if (j.second - i > numr) dnc(rbound + 1, r, j.first + i, numr);
			}
			return;
		}
	}
}

int find_best(int n) {
	cache.resize(n, {-1, -1});
	int firstl = 0;
	for (int i = 0; i < min(n, 474) && lolpop <= 26; i++) {
		auto j = qry(i);
		if (ans != -1) return ans;
		if (j.first + j.second > lolpop) {
			lolpop = j.first + j.second;
			firstl = i;
		}
	}
	dnc(firstl, n - 1, firstl, 0);
	return ans;
}

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