Submission #393507

#	Time	Username	Problem	Language	Result	Execution time	Memory
393507		JimmyZJX	The Big Prize (IOI17_prize)	C++14	0 / 100	6 ms	268 KiB

prize

#include <iostream>
#include <fstream>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cassert>
#include <tuple>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <unordered_set>
#include <unordered_map>
#include <numeric>

using namespace std;

typedef long long LL;
typedef vector<int> Vi;
typedef vector<LL> VL;
typedef vector<bool> Vb;
typedef vector<vector<int>> Vii;

#define forR(i, n) for (int i = 0; i < (n); i++)

Vi ask(int i);

int cntV = 0, N;

int getLeftNonVCnt(int i) {
	int c = 0;
	while (true) {
		if (i >= N) return N - cntV;
		Vi rs = ask(i);
		if (rs[0] + rs[1] == N - cntV) {
			// is a V node
			return rs[0] - c;
		} else {
			i++;
			c++;
		}
	}
}

int find_best(int n) {
	N = n;

	if (n <= 5000) {
		forR(i, n) {
			Vi rs = ask(i);
			if (rs[0] == 0 && rs[1] == 0)
				return i;
		}
	} else {
		cntV = 0;
		forR(i, 500) {
			Vi rs = ask(i);
			if (rs[0] == 0 && rs[1] == 0) return i;
			cntV = max(cntV, n - rs[0] - rs[1]);
		}

		int cntNotV = n - cntV;

		for (int t = 0; t < cntNotV; t++) {
			// goal: get the t-th non-V node
			int l = 0, r = n - 1;

			while (l < r) {
				int mid = (l + r) / 2;
				if (getLeftNonVCnt(mid + 1) >= t) {
					r = mid;
				} else {
					l = mid + 1;
				}
			}
			// l is the t-th non-V node
			Vi rs = ask(l); if (rs[0] == 0 && rs[1] == 0) return l;
		}

		return -1;
	}

	int l = 0, r = n - 1;

	while (l < r) {
		int mid = (l + r) / 2;
		Vi rs = ask(mid);
		if (rs[0] == rs[1]) return mid;
		if (rs[0] == 1) {
			r = mid - 1;
		} else {
			l = mid + 1;
		}
	}

	return l;
}

#ifdef TEST_LOCAL
Vi _answer{ 2,2,1,2,2,2,2,2,2,2,2,2 };
Vi ask(int i) {
	int n = _answer.size();
	assert(i >= 0 && i < n);
	int l = 0, r = 0;
	for (int j = 0; j < n; j++) {
		if (_answer[j] < _answer[i]) {
			if (j < i) l++; else r++;
		}
	}
	return Vi{ l, r };
}

int main() {
	auto r = find_best(_answer.size());

	return 0;
}
#endif

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