Submission #769837

#	Time	Username	Problem	Language	Result	Execution time	Memory
769837		marvinthang	Counting Mushrooms (IOI20_mushrooms)	C++17	100 / 100	7 ms	480 KiB

mushrooms

/*************************************
*    author: marvinthang             *
*    created: 30.06.2023 10:50:39    *
*************************************/

#include "mushrooms.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

int count_mushrooms(int n) {
	int nd = 8;
	int mn = 203;

	vector <vector <vector <int>>> ask{{{0}}};
	vector <vector <int>> order {{0}};
	vector <int> max_len {1}, min_last {3};
	FOR(i, 1, nd) {
		int last = max_len[i - 1];
		int add = MASK(i - 1) - 1;
		max_len.push_back(max_len.back() * 2 + add);
		vector <vector <int>> nxt;
		REP(j, add) {
			vector <int> m = ask.back()[j];
			vector <int> n = ask.back()[j];
			int k = 0;
			for (int x: ask.back()[j]) {
				m.push_back(x + last);
				while (k < x) n.push_back(last + k++);
				k++;
			}
			while (k < last) n.push_back(last + k++);
			m.push_back(2 * last + j);
			nxt.push_back(m);
			nxt.push_back(n);
		}
		vector <int> k;
		REP(j, last) k.push_back(last + j);
		nxt.push_back(k);

		k.clear();
		REP(j, last) k.push_back(j);
		REP(j, add) k.push_back(2 * last + j);
		nxt.push_back(k);

		ask.push_back(nxt);

		vector <int> ord(MASK(i));
		iota(ALL(ord), 0);
		sort(ALL(ord), [&] (int a, int b) { return nxt[a].size() < nxt[b].size(); });
		order.push_back(ord);
		int ml = 0;
		REP(j, MASK(i)) maximize(ml, (int) nxt[ord[j]].size() * 2 + 1 - j);
		min_last.push_back(ml);
	}

	vector <int> dp(mn + 1), trace(mn + 1);
	dp[0] = 1;
	dp[1] = 2;
	dp[2] = 3;

	int best = mn + 1, p = -1;

	FORE(i, 2, mn) {
		if (dp[i] > n) break;
		int num_query = i;
		int pos = dp[i];
		int sz = dp[i];
		while (pos < n) {
			pos += (sz + 1) / 2;
			sz++;
			++num_query;
		}
		if (minimize(best, num_query)) p = i;

		REP(j, nd) if (dp[i] >= min_last[j] && i + MASK(j) <= mn && maximize(dp[i + MASK(j)], dp[i] + max_len[j] + MASK(j)))
			trace[i + MASK(j)] = j;
	}
	
	vector <int> t_add;
	while (p > 2) {
		t_add.push_back(trace[p]);
		p -= MASK(trace[p]);
	}
	reverse(ALL(t_add));

	vector <vector <int>> pos(2);
	pos[0].push_back(0);
	pos[use_machine(vector<int>{0, 1})].push_back(1);
	if (n == 2) return pos[0].size();
	pos[use_machine(vector<int>{0, 2})].push_back(2);
	int i = 3;

	function <vector<int>(int, vector<int>)> solve = [&] (int t, vector <int> cur) {
		if (!t) return cur;
		int n = cur.size();
		vector <int> left, right, add;
		int sum_left = cur[n - 1] - cur[n - 2];
		int sum_right = cur[n - 2];
		for (int i = 0; i + 2 < n; i += 2) {
			left.push_back((cur[i] + cur[i + 1] - sum_right) / 2);
			right.push_back((cur[i] - cur[i + 1] + sum_right) / 2);
			add.push_back((cur[i] + cur[i + 1] + sum_right) & 1);
			sum_left -= add.back();
		}
		left.push_back(sum_left);
		right.push_back(sum_right);
		left = solve(t - 1, left);
		right = solve(t - 1, right);
		left.insert(left.end(), ALL(right));
		left.insert(left.end(), ALL(add));
		return left;
	};

	for (int t: t_add) {
		int sz = MASK(t);
		int add = max_len[t];
		vector <int> res(sz);
		REP(_, sz) {
			bool p = pos[0].size() < pos[1].size();
			int k = order[t][_];
			vector <int> v;
			v.push_back(i + add + _);
			v.push_back(pos[p][0]);

			REP(j, ask[t][k].size()) {
				v.push_back(i + ask[t][k][j]);
				v.push_back(pos[p][j + 1]);
			}
			int cur = use_machine(v);
			res[k] = p ? (int) ask[t][k].size() - cur / 2 : cur / 2;
			pos[p ^ (cur & 1)].push_back(v[0]);
		}
		if (t) res[sz - 1] += res[sz - 2];
		vector <int> v = solve(t, res);
		REP(j, add) pos[v[j]].push_back(i + j);
		i += add + sz;
	}

	int cnt_0 = pos[0].size();
	for (; i < n; ) {
		bool p = pos[0].size() < pos[1].size();
		vector <int> v;
		int j = 0;
		for (; j < min(n - i, (int) pos[p].size()); ++j) {
			v.push_back(i + j);
			v.push_back(pos[p][j]);
		}
		int cur = use_machine(v);
		cnt_0 += p ? (cur + 1) / 2 : j - (cur + 1) / 2;
		pos[p ^ (cur & 1)].push_back(i);
		i += j;
	}
	return cnt_0;
}

• Subtask 1: 100 / 100