Submission #162174

#	Time	Username	Problem	Language	Result	Execution time	Memory
162174		kostia244	Split the sequence (APIO14_sequence)	C++14	60 / 100	2061 ms	76144 KiB

sequence

//#pragma comment(linker, "/stack:200000000")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
#include<bits/extc++.h>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define pb push_back
using namespace std;
using namespace __gnu_pbds;
using ll = long long;
using vi = vector<ll>;
using vvi = vector<vector<ll>>;
const ll mod = 998244353;
using oset = tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
using vec = complex<ll>;
using ld = long double;
using vld = complex<ld>;
ll dot(vec a, vec b) {
	return (conj(a) * b).real();
}
ll cross(vec a, vec b) {
	return (conj(a) * b).imag();
}
struct cht {
	vector<vec> hull;
	void clear() {
		hull.clear();
	}
	bool nok(ld x, ld y, ld x1, ld y1, ld x2, ld y2) {
		vld a(x1 - x, y1 - y);
		vld b(x2 - x1, y2 - y1);
		return (conj(a) * b).imag() > -(1e-3);
	}
	bool rem() {
		int n = hull.size();
		if (n < 3)
			return 0;
		return nok(hull[n - 3].real(), hull[n - 3].imag(), hull[n - 2].real(),
				hull[n - 2].imag(), hull[n - 1].real(), hull[n - 1].imag());
	}
	void add(vec x) {
		hull.pb(x);
		while (rem())
			swap(hull.back(), hull[hull.size() - 2]), hull.pop_back();
	}
	vec get(vec x) {
		ll l = 0, r = (int)hull.size() - 1, a, b;
		while (r - l > 3) {
			a = l + (r - l) / 3;
			b = r - (r - l) / 3;
			if (dot(x, hull[a]) < dot(x, hull[b]))
				l = a;
			else
				r = b;
		}
		ll ans = 0;
		vec z;
		while (l <= r) {
			ans = max(ans, dot(x, hull[l]));
			if(ans==dot(x, hull[l]))
				z=hull[l];
			l++;
		}
		return z;
	}
};

const int MK = 220, MN = 1e5 + 3;
ll n, a[MN], pref[MN], dp[MK][MN], p[MK][MN];
ll f(ll l, ll r, ll i) {
	ll a = pref[i] - pref[l - 1];
	ll b = pref[r] - pref[i];
	return a * b;
}
void bt(int a, int b) {
	cout << b << " ";
	if (a > 1)
		bt(a - 1, p[a][b]);
}
#define val(j) ((dp[a - 1][(j) - 1] + f(j, n, i)))
int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	ll k;
	map<ll, int> bc;
	cin >> n >> k;
	for (int i = 1; i <= n; i++) {
		cin >> a[i], pref[i] = pref[i - 1] + a[i];
		if (a[i])
			bc[pref[i]] = i;
	}
	ll ans = -1, g = n - 1;
	cht x;
	for (int a = 1; a <= k; a++) {
		x.clear();
//		if(a==1)
		x.add(vec(0, 0));
		for (int i = 1; i < n; i++) {
			if(i>=a) {
			vec t = x.get(vec(1, pref[n]-pref[i]));
			dp[a][i] = dot(t, vec(1, pref[n]-pref[i])) + pref[i]*(pref[n]-pref[i]);
			p[a][i] = bc[-t.imag()];
//			cout << -t.real() << " ";
			ans = max(ans, dp[a][i]);
			if (ans == dp[a][i])
				g = i;
			}else dp[a][i] = dp[a-1][i];
			x.add(vec(dp[a - 1][i], -pref[i]));
		}
	}

	cout << ans << '\n';
	bt(k, g);
}

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