Submission #94849

#	Time	Username	Problem	Language	Result	Execution time	Memory
94849		aminra	Split the sequence (APIO14_sequence)	C++14	71 / 100	2041 ms	43084 KiB

sequence

//Smaug never desolated!!
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int MAXN = (int)1e5 + 3;
const int MAXS = (int)203;
const int MOD = (int)1e9 + 7;
const int infint = (int)1e9;
const ll inf = (ll)1e15;
bool Q;
struct Line 
{
	mutable ll k, m, p, id;
	bool operator<(const Line& o) const 
	{
		return Q ? p < o.p : k < o.k;
	}
};
struct CHT : multiset<Line> 
{
	// (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));
	}
	ll query(ll x) 
	{
		assert(!empty());
		Q = 1; 
		auto l = *lower_bound({0, 0, x});
		Q = 0;
		return l.k * x + l.m;
	}
	ll getid(ll x)
	{
		assert(!empty());
		Q = 1; 
		auto l = *lower_bound({0, 0, x});
		Q = 0;
		return l.id;
	}
};
ll n, k, dp[MAXS][MAXN], par[MAXS][MAXN], a[MAXN], part[MAXN];
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	cin >> n >> k;
	for (int i = 1; i <= n; i++)
		cin >> a[i];
	for (int i = 1; i <= n; i++)
		part[i] = part[i - 1] + a[i];
	for (int i = 1; i <= k; i++)
	{
		CHT cur;
		cur.add(part[i], dp[1 - i % 2][i] - part[i] * part[i], i);
		for (int j = i + 1; j <= n; j++)
		{
			dp[i % 2][j] = cur.query(part[j]);
			par[i][j] = cur.getid(part[j]);
			cur.add(part[j], dp[1 - i % 2][j] - part[j] * part[j], j);
		}
	}
	cout << dp[k % 2][n] << "\n";
	int t = k, last = n;
	while(t)
	{
		cout << par[t][last] << " ";
		last = par[t][last];
		t--;
	}
}

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