Submission #765682

#	Time	Username	Problem	Language	Result	Execution time	Memory
765682		marvinthang	The Big Prize (IOI17_prize)	C++17	97.66 / 100	46 ms	5328 KiB

prize

/*************************************
*    author: marvinthang             *
*    created: 25.06.2023 08:50:11    *
*************************************/

#include "prize.h"
#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

// end of template

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); 
template <class T> T rand(T l, T h) { return uniform_int_distribution <T> (l, h) (rng); } 
template <class T> T rand(T h) { return uniform_int_distribution <T> (0, h - 1) (rng); } 

int ma, res;
vector <vector <int>> f;
vector <int> ASK(int i) {
	if (f[i].empty()) f[i] = ask(i);
	return f[i];
}
void solve(int l, int r, int cl, int cr) {
	if (~res || l > r || cl + cr == ma) return;
	int m = l + r >> 1;
	vector <int> a = ASK(m);
	if (!a[0] && !a[1]) {
		res = m;
		return;
	}
	if (a[0] + a[1] == ma) {
		solve(l, m - 1, cl, a[1]);
		solve(m + 1, r, a[0], cr);
		return;
	}
	int i = m;
	while (--i >= l) {
		a = ASK(i);
		if (!a[0] && !a[1]) {
			res = i;
			return;
		}
		if (a[0] + a[1] == ma) break;
	}
	if (i < l) {
		solve(m + 1, r, cl + m - l + 1, cr);
	} else {
		solve(l, i - 1, cl, a[1]);
		solve(m + 1, r, a[0] + m - i, cr);
	}
}

int find_best(int n) {
	res = -1;
	f.assign(n, vector<int>());
	ma = 0;
	REP(t, 500) {
		int i = rand(n);
		vector <int> a = ASK(i);
		if (!a[0] && !a[1]) return i;
		maximize(ma, a[0] + a[1]);
	}
	solve(0, n - 1, 0, 0);
	return res;
}

#ifdef LOCAL
#include "prize.h"

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

using namespace std;

static const int max_q = 5000;
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;
}

int main() {
	file("prize");
	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);
	if (g[res] != 1) return !(cout << "WA!\n");
	cout << res << endl << "Query count: " << query_count << endl;

	return 0;
}
#endif

Compilation message (stderr)

prize.cpp: In function 'void solve(int, int, int, int)':
prize.cpp:60:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   60 |  int m = l + r >> 1;
      |          ~~^~~

• Subtask 1: 20 / 20
• Subtask 2: 77.66 / 80