Submission #52169

#	Time	Username	Problem	Language	Result	Execution time	Memory
52169		ernestvw	The Big Prize (IOI17_prize)	C++11	97.55 / 100	91 ms	11580 KiB

prize

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

#include "prize.h"
//vector<int> ask(int i);

vector<int> series;

int N;

vector<int> memo[200001];
vector<int> query(int i) {
	if(i == -42) return {2*N, 2*N};
	if(i < 0 or i > N-1)
		return {0, 0};
	if(memo[i][0] != -1) return memo[i];
	else return memo[i] = ask(i);
}

/*int find(int l, int r) {
	if(l == r) return l;
	int mid = (l+r)/2;
	vector<int> q = query(mid);
	if(q[0] == 0 and q[1] == 0) return mid;
	else if(q[0] == 0) return find(mid+1, r);
	return find(l, mid-1);
}*/

bool bigger(int i, int j) {
	vector<int> q1 = query(i);
	vector<int> q2 = query(j);
	return q1[0] + q1[1] < q2[0] + q2[1];
}

int MINI = -1;

bool ok(int i) {
	vector<int> q = query(i);
	return MINI == q[0] + q[1];
}

int L(int i) {
	vector<int> q = query(i);
	return q[0];
}

int R(int i) {
	vector<int> q = query(i);
	return q[1];
}

int S(int i) {
	vector<int> q = query(i);
	return q[0] + q[1];
}

int find(int l, int r) {
	if(l > r or l < 0 or r > N-1) return -42;
	if(l == r) return l;
	int rB = R(r+1);
	int lB = L(l-1);
	int mid = (l + r) / 2;
	vector<int> q = query(mid);
	vector<int> candidates = {mid};
	if(R(mid) - rB != 0) candidates.push_back(find(mid+1, r));
	if(L(mid) - lB != 0) candidates.push_back(find(l, mid-1));
	int ans = -1;
	int mini = N+1;
	for(int i : candidates) if(S(i) < mini) mini = S(i), ans = i;
	return ans;
}

int solve() {
	/*if(N <= 5000) {
		for(int i = 0; i < N; i++) {
			vector<int> q = query(i);
			if(q[0] + q[1] == 0) return i;
		}
	}*/
	return find(0, N-1);
}

int find_best(int n) {
	series.clear();
	long long cur = 1;
	series.push_back(cur);
	while(cur * cur + 1LL < (long long)n) {
		series.push_back(cur * cur + 1LL);
		cur = cur * cur + 1LL;
	}
	N = n;
	for(int i = 0; i < N; i++) memo[i] = {-1, -1};
	//return find(0, N-1);
	return solve();
}

• Subtask 1: 20 / 20
• Subtask 2: 77.55 / 80