Submission #104210

#	Time	Username	Problem	Language	Result	Execution time	Memory
104210		RockyB	The Big Prize (IOI17_prize)	C++17	96.98 / 100	54 ms	928 KiB

prize

/// In The Name Of God
 
#include <bits/stdc++.h>
#ifndef IOI2018
#include "prize.h"
#endif
 
#define f first
#define s second
 
#define pb push_back
#define pp pop_back
#define mp make_pair
 
#define sz(x) (int)x.size()
#define sqr(x) ((x) * 1ll * (x))
#define all(x) x.begin(), x.end()
 
#define rep(i, l, r) for (int i = (l); i < (r); i++)
#define per(i, l, r) for (int i = (l); i >= (r); i--)
 
#define Kazakhstan ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);
 
#define nl '\n'
#define ioi exit(0);
 
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
 
const int N = (int)5e5 + 7;
const int inf = (int)1e9 + 7;
const int mod = (int)1e9 + 7;
const ll linf = (ll)1e18 + 7;
 
const int dx[] = {-1, 0, 1, 0, 1, -1, -1, 1};
const int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};
 
using namespace std;
 
namespace com {
	static const int max_q = 5000;
	static int n;
	static int query_count = 0;
	static vector<int> g;
	static vector<vector<int> > rank_count;
 
}
 
namespace grader {
	using namespace com;
	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;
	}
}
#ifdef IOI2018
using namespace grader;
#endif
 
const int K = 500;
map <int, vector <int > > dp;
  
vector <int> get(int p) {
	if (dp.count(p)) return dp[p];
	return dp[p] = ask(p);
}
int mx;
int tin;
 
/// (n - 1) / k + cnt * 
int solve(int p, int n) {
	if (p >= n) {
		return -1;
	}
 
	{
		while (1) {
			vector <int> now = get(p);
			if (now[0] + now[1] == 0) return p;
			if (now[0] + now[1] == mx) break;
			p++;
		}
	}
	/*
	vector <int> _c = get(p);
	for (auto it : dp) {
			if (it.f >= p && (it.s[0] == 0 || it.s[0] == _c[0])) {
				p = it.f;
			}
		}*/
	int l = p / K + 1, r = (n - 1) / K, res = p / K;
	vector <int> cur = get(p);
	while (l <= r) {
		int mid = l + r >> 1;
		vector <int> now = get(K * mid);
		if (now[0] + now[1] == 0) return K * mid;
		if (cur == now) res = mid, l = mid + 1;
		else r = mid - 1;
	}

	l = max(p, res * K);
	r = min(n - 1, (res + 1) * K - 1);
	int nxt = -1;
	while (l <= r) {
		int mid = l + r >> 1;
		vector <int> now = get(mid);
		if (now[0] + now[1] == 0) return mid;
		if (cur == now) nxt = mid, l = mid + 1;
		else r = mid - 1;
	}
	++nxt;
	return solve(nxt, n);
}
int find_best(int n) {
	int id = -1;
	int cnt = min(n, 473), done = 0;
  rep(i, n - 1 - cnt + 1, n - 1) {
		vector <int> cur = ask(i);
		if (!max(cur[0], cur[1])) {
			return i;
		}
		mx = cur[0] + cur[1];
	}
	return solve(0, n);
} 
 
 
namespace read {
	using namespace com;
	void read() {
		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;
		ioi
		cout << res << endl << "Query count: " << query_count << endl;
		ioi
	}
}
 
#ifdef IOI2018
int main() {
	#ifdef IOI2018
		freopen ("in.txt", "r", stdin);
		freopen ("D.out", "w", stdout);
	#endif
	read :: read();
}
#endif

Compilation message (stderr)

prize.cpp: In function 'int solve(int, int)':
prize.cpp:108:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   int mid = l + r >> 1;
             ~~^~~
prize.cpp:119:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   int mid = l + r >> 1;
             ~~^~~
prize.cpp: In function 'int find_best(int)':
prize.cpp:129:6: warning: unused variable 'id' [-Wunused-variable]
  int id = -1;
      ^~
prize.cpp:130:25: warning: unused variable 'done' [-Wunused-variable]
  int cnt = min(n, 473), done = 0;
                         ^~~~

• Subtask 1: 20 / 20
• Subtask 2: 76.98 / 80