Submission #104549

#	Time	Username	Problem	Language	Result	Execution time	Memory
104549		KCSC	The Big Prize (IOI17_prize)	C++14	100 / 100	45 ms	532 KiB

prize

#ifndef HOME
	#include "prize.h"
#endif

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

#ifdef HOME

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

static const int max_q = 10000;
static int n;
static int query_count = 0;
static vector<int> g;
static vector<vector<int> > rank_count;

vector<int> ask(int i) {
	query_count++;
	if(query_count > max_q) {
		cerr << "Query limit exceeded" << endl;
		exit(0);
	}

	if(i < 0 || i >= n) {
		cerr << "Bad index: " << i << endl;
		exit(0);
	}

	vector<int> res(2);
	res[0] = rank_count[g[i] - 1][i + 1];
	res[1] = rank_count[g[i] - 1][n] - res[0];
	return res;
}
#endif

void solve(int le, int ri, vector<int> lef, vector<int> rig, int &ans) {
	if (ans != -1) {	
		return; }
	if (lef[0] + lef[1] == 0) {
		ans = le; return; }
	if (rig[0] + rig[1] == 0) {
		ans = ri; return; }
	if (le >= ri - 1) {
		return; }
	if (lef[0] + lef[1] == rig[0] + rig[1] and lef[0] == rig[0]) {
		return; }
	if (lef[0] + lef[1] < rig[0] + rig[1]) {
		solve(le + 1, ri, ask(le + 1), rig, ans); return; }
	if (lef[0] + lef[1] > rig[0] + rig[1]) {
		solve(le, ri - 1, lef, ask(ri - 1), ans); return; }
	int md = (le + ri) >> 1;
	vector<int> aux = ask(md);
	solve(le, md, lef, aux, ans);
	solve(md, ri, aux, rig, ans); }

int find_best(int n) {
	int ans = -1;
	solve(0, n - 1, ask(0), ask(n - 1), ans);
	return ans; }

#ifdef HOME
int main() {
	freopen("prize.in", "r", stdin);
	freopen("prize.out", "w", stdout);
	cin >> n;

	g.resize(n);
	for(int i = 0; i < n; i++) {
		cin >> g[i];
		if(g[i] < 1) {
			cerr << "Invalid rank " << g[i] << " at index " << i << endl;
			exit(0);
		}
	}

	int max_rank = *max_element(g.begin(), g.end());

	rank_count.resize(max_rank + 1, vector<int>(n + 1, 0));
	for(int r = 0; r <= max_rank; r++) {
		for(int i = 1; i <= n; i++) {
			rank_count[r][i] = rank_count[r][i - 1];
			if(g[i - 1] == r)
			  rank_count[r][i]++;
		}
	}

	for(int i = 0; i <= n; i++)
		for(int r = 1; r <= max_rank; r++)
			rank_count[r][i] += rank_count[r - 1][i];

	int res = find_best(n);
	cout << res << endl << "Query count: " << query_count << endl;

	return 0;
}
#endif

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