제출 #231418

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
231418		peijar	수열 (APIO14_sequence)	C++17	71 / 100	2089 ms	108848 KiB

sequence

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

#define SZ(v) ((int)(v).size())
using ll = long long;

struct Line {
	mutable ll k, m, p, id;
	bool operator<(const Line& o) const { return k < o.k; }
	bool operator<(ll x) const { return p < x; }
};

struct LineContainer : multiset<Line, less<>> {
	// (for doubles, use inf = 1/.0, div(a,b) = a/b)
	const ll inf = LLONG_MAX;
	ll div(ll a, ll b) { // floored division
		return a / b - ((a ^ b) < 0 && a % b); }
	bool isect(iterator x, iterator y) {
		if (y == end()) { x->p = inf; return false; }
		if (x->k == y->k) x->p = x->m > y->m ? inf : -inf;
		else x->p = div(y->m - x->m, x->k - y->k);
		return x->p >= y->p;
	}
	void add(ll k, ll m, ll id) {
		auto z = insert({k, m, 0, id}), y = z++, x = y;
		while (isect(y, z)) z = erase(z);
		if (x != begin() && isect(--x, y)) isect(x, y = erase(y));
		while ((y = x) != begin() && (--x)->p >= y->p)
			isect(x, erase(y));
	}
	pair<ll, int> query(ll x) {
		assert(!empty());
		auto l = *lower_bound(x);
		return make_pair(l.k * x + l.m, l.id);
	}
};

const int MAXN = 1e5+1;
const int MAXK = 201;

ll dp[MAXK][MAXN];

ll arr[MAXN];
ll transition[MAXK][MAXN];

int nb_elem;


int main(void)
{
	int nb_split;
	cin >> nb_elem >> nb_split;
	for (int i(0); i < nb_elem; ++i)
		cin >> arr[i];

	vector<ll> suffix_sum(nb_elem+1);
	suffix_sum[nb_elem] = 0;
	for (int i(nb_elem-1); i >= 0; --i)
		suffix_sum[i] = suffix_sum[i+1] + arr[i];
	for (int splits(1); splits <= nb_split; ++splits)
		dp[splits][nb_elem-1] = -2e18;

	for (int splits(1); splits <= nb_split; ++splits)
	{
		LineContainer lichao;
		for (int id(nb_elem -2); id >= 0; --id)
		{
			if (dp[splits-1][id+1] >= 0)
				lichao.add(suffix_sum[id+1], dp[splits-1][id+1] - suffix_sum[id+1] * suffix_sum[id+1], id);
			if (id == nb_elem - 1)
				continue;
			if (!lichao.empty())
			{
				auto [val, nxt] = lichao.query(suffix_sum[id]);
				dp[splits][id] = val;
				transition[splits][id] = nxt;
			}
			else
				dp[splits][id] = -2e18;
		}
	}

	cout << dp[nb_split][0] << endl;

	int cur(0);
	for (int i(0); i < nb_split; ++i)
	{
		assert(dp[nb_split-i][cur] >= 0);
		cur = transition[nb_split-i][cur] + 1;
		cout << cur << ' ';
	}
	cout << endl;

}

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 0 / 29