Submission #961374

#	Time	Username	Problem	Language	Result	Execution time	Memory
961374		Bungmint	Cake 3 (JOI19_cake3)	C++17	100 / 100	696 ms	13776 KiB

cake3

// Copyright © 2024 Youngmin Park. All rights reserved.
//#pragma GCC optimize("O3")
//#pragma GCC target("avx2")
#include <bits/stdc++.h>
using namespace std;

#pragma region TEMPLATE

using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;
using vpi = vector<pii>;
using pll = pair<ll, ll>;
using vl = vector<ll>;
using vpl = vector<pll>;
using ld = long double;
template <typename T, size_t SZ>
using ar = array<T, SZ>;
template <typename T>
using pqg = priority_queue<T, vector<T>, greater<T>>;

#define all(v) (v).begin(), (v).end()
#define pb push_back
#define eb emplace_back
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound

constexpr int INF = 1e9;
constexpr ll LINF = 1e18;
const ld PI = acos((ld)-1.0);
constexpr int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T>
constexpr bool ckmin(T &a, const T &b) { return b < a ? a = b, 1 : 0; }
template <typename T>
constexpr bool ckmax(T &a, const T &b) { return b > a ? a = b, 1 : 0; }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); } // divide a by b rounded down

#ifdef LOCAL
#include "miscellaneous/debug.h"
#else
#define dbg(...) 42
#endif

#pragma endregion TEMPLATE

/**
 * Description: Performs range prefix sum queries and point updates. lower_bound returns the first prefix sum >= v
 * Source: Own
 * Verification: http://www.usaco.org/index.php?page=viewproblem2&cpid=693
 * Time Complexity: O(log n) for query and update
 * 0-indexing
 */

template <typename T>
struct BIT {
	int N; vector<T> bit;
	BIT(int n) : N(n), bit(n + 1) {}
	void upd(int id, T v) {
		for (id++; id <= N; id += id & -id)
			bit[id] += v;
	}
	T query(int id) {
		T res = 0;
		for (id++; id > 0; id -= id & -id)
			res += bit[id];
		return res;
	}
	T query(int l, int r) {
		return l > r ? 0 : query(r) - query(l - 1);
	}
	T lower_bound(T v) {
		int id = 0;
		T sum = 0;
		int lg = 31 - __builtin_clz(N);
		for (int j = lg; ~j; j--) {
			if (id + (1 << j) <= N && sum + bit[id + (1 << j)] < v) {
				id += (1 << j);
				sum += bit[id];
			}
		}
		return id;
	}
};


void solve() {
	int n, m;
	cin >> n >> m;
	vl cost(n), val(n), ind(n), order;
	for (int i = 0; i < n; i++) cin >> val[i] >> cost[i], order.pb(val[i]);
	iota(all(ind), 0);
	sort(all(ind), [&](int i, int j) { return cost[i] < cost[j]; });
	sort(all(order));
	order.resize(unique(all(order)) - begin(order));
	int k = sz(order);
	BIT<ll> bit(k), ex(k);
	for (int i = 0; i < n; i++) {
		val[i] = lb(all(order), val[i]) - begin(order);
		val[i] = k - 1 - val[i];
	}
	int lef = 0, rig = -1;
	auto upd = [&](int l, int r) -> void {
		while (rig < r) {
			rig++;
			int id = val[ind[rig]];
			bit.upd(id, 1);
			ex.upd(id, 1LL * order[k - 1 - id]);
		}
		while (lef > l) {
			lef--;
			int id = val[ind[lef]];
			bit.upd(id, 1);
			ex.upd(id, 1LL * order[k - 1 - id]);
		}
		while (rig > r) {
			int id = val[ind[rig]];
			bit.upd(id, -1);
			ex.upd(id, -1LL * order[k - 1 - id]);
			rig--;
		}
		while (lef < l) {
			int id = val[ind[lef]];
			bit.upd(id, -1);
			ex.upd(id, -1LL * order[k - 1 - id]);
			lef++;
		}
	};
	auto get_top_m = [&]() -> ll {
		int i = bit.lower_bound(m) - 1;
		int todo = m - bit.query(i);
		return ex.query(i) + 1LL * todo * order[k - 2 - i];
	};

	ll ans = -LINF;
	auto solver = [&](int l, int r, int optl, int optr, auto&& self) -> void {
		if (l > r) return;
		int mid = (l + r) / 2;
		int optm = -1;
		ll opt = -LINF;
		for (int i = optl; i <= optr; i++) {
			if (i < mid + m - 1) continue;
			upd(mid, i);
			if (ckmax(opt, get_top_m() - 2 * (cost[ind[i]] - cost[ind[mid]]))) {
				optm = i;
			}
		}
		ckmax(ans, opt);
		if (opt == -LINF) {
			self(l, mid - 1, optl, optr, self);
		} else {
			self(l, mid - 1, optl, optm, self);
			self(mid + 1, r, optm, optr, self);
		}
	};
	solver(0, n - 1, 0, n - 1, solver);
	cout << ans << '\n';
}

int main() {
	cin.tie(0)->sync_with_stdio(0);
	cin.exceptions(cin.failbit);
	int testcase = 1;
	// cin >> testcase;
	while (testcase--) {
		solve();
	}
#ifdef LOCAL
	cerr << "Time elapsed: " << 1.0 * (double)clock() / CLOCKS_PER_SEC << " s.\n";
#endif
}

Compilation message (stderr)

cake3.cpp:7: warning: ignoring '#pragma region TEMPLATE' [-Wunknown-pragmas]
    7 | #pragma region TEMPLATE
      | 
cake3.cpp:49: warning: ignoring '#pragma endregion TEMPLATE' [-Wunknown-pragmas]
   49 | #pragma endregion TEMPLATE
      |

• Subtask 1: 5 / 5
• Subtask 2: 19 / 19
• Subtask 3: 76 / 76