Submission #591004

#	Time	Username	Problem	Language	Result	Execution time	Memory
591004		dutinmeow	Election (BOI18_election)	C++17	100 / 100	486 ms	44812 KiB

election

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

#pragma region y_combinator

#ifndef Y_COMBINATOR_HPP
#define Y_COMBINATOR_HPP

template<class Fun>
class y_combinator_result {
	Fun fun_;
public:
	template<class T>
	explicit y_combinator_result(T &&fun) : fun_(std::forward<T>(fun)) {}

	template<class ...Args>
	decltype(auto) operator()(Args &&...args) {
		return fun_(std::ref(*this), std::forward<Args>(args)...);
	}
};

template<class Fun>
decltype(auto) y_combinator(Fun &&fun) {
	return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun));
}

#endif

#pragma endregion y_combinator

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);

	int N;
	string S;
	cin >> N >> S;
	vector<int> A(N);
	for (int i = 0; i < N; i++)
		A[i] = S[i] == 'C' ? 1 : -1;

	using st_node_t = struct { int pre, suf, ans, sum; };
	vector<st_node_t> st_tree(4 * N);

	auto st_pull = [&](const st_node_t &a, const st_node_t &b) -> st_node_t {
		return st_node_t{
			max(a.pre, a.sum + b.pre),
			max(b.suf, b.sum + a.suf),
			max({a.ans, b.ans, a.suf + b.pre}),
			a.sum + b.sum
		};
	};

	y_combinator([&](auto st_build, int t, int tl, int tr) -> void {
		if (tl == tr) {
			st_tree[t] = st_node_t{max(A[tl], 0), max(A[tl], 0), max(A[tl], 0), A[tl]};
			return;
		}
		int tm = (tl + tr) / 2;
		st_build(t * 2, tl, tm);
		st_build(t * 2 + 1, tm + 1, tr);
		st_tree[t] = st_pull(st_tree[t * 2], st_tree[t * 2 + 1]);
	})(1, 0, N - 1);

	auto st_query = y_combinator([&](auto st_query, int l, int r, int t, int tl, int tr) -> st_node_t {
		if (l > r)
			return st_node_t{0, 0, 0, 0};
		if (l <= tl && tr <= r)
			return st_tree[t];
		int tm = (tl + tr) / 2;
		if (r <= tm)
			return st_query(l, r, t * 2, tl, tm);
		if (tm < l)
			return st_query(l, r, t * 2 + 1, tm + 1, tr);
		return st_pull(st_query(l, r, t * 2, tl, tm), st_query(l, r, t * 2 + 1, tm + 1, tr));
	});

	int Q;
	cin >> Q;
	while (Q--) {
		int l, r;
		cin >> l >> r;
		l--, r--;
		auto q = st_query(l, r, 1, 0, N - 1);
		cout << q.ans - q.sum << '\n';
	}
}

Compilation message (stderr)

election.cpp:4: warning: ignoring '#pragma region y_combinator' [-Wunknown-pragmas]
    4 | #pragma region y_combinator
      | 
election.cpp:29: warning: ignoring '#pragma endregion y_combinator' [-Wunknown-pragmas]
   29 | #pragma endregion y_combinator
      |

• Subtask 1: 28 / 28
• Subtask 2: 54 / 54
• Subtask 3: 18 / 18