Submission #384061

#	Time	Username	Problem	Language	Result	Execution time	Memory
384061		Drew_	Split the sequence (APIO14_sequence)	C++14	100 / 100	1411 ms	81516 KiB

sequence

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
 
#pragma GCC target ("avx2")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")
 
#define ll long long
#define pb push_back
 
const int MAX = 1e5 + 7;
 
int n;
ll pfx[MAX];
ll dp[2][MAX];
int par[201][MAX];
void rc(int k, int l, int r, int optL, int optR)
{
	if (l > r)
		return;
 
	int mid = (l + r) / 2;
	ll optVal = -1, optIdx = -1;
 
	for (int i = optL; i <= mid && i <= optR; ++i)
	{
		//segment [i, n], cut at mid
		ll v = dp[(k+1)&1][i-1] + (pfx[mid] - pfx[i-1]) * (pfx[n] - pfx[mid]);
		if (v > optVal)
		{
			optVal = v;
			optIdx = i;
		}
	}
 
	dp[k&1][mid] = optVal;
	par[k][mid] = optIdx;
 
	rc(k, l, mid-1, optL, optIdx);
	rc(k, mid+1, r, optIdx, optR);
}
 
int main()
{
	ios :: sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
 
	int k;
	cin >> n >> k;
 
	for (int i = 1; i <= n; ++i)
		cin >> pfx[i], pfx[i] += pfx[i-1];
 
	for (int i = 1; i <= n; ++i)
		dp[0][i] = 0;
 
	for (int i = 1; i <= k; ++i)
		rc(i, i, n, i, n);
 
	ll res = -1, idx = -1;
	for (int i = 1; i <= n; ++i)
	{
		if (res < dp[k&1][i])
			res = dp[k&1][i], idx = i;
	}
 
	vector<int> cut;
	cut.pb(idx);
	for (int j = k; j >= 2; --j)
		cut.pb(idx = par[j][idx] - 1);

	cout << res << '\n';
	for (int i = k-1; i >= 0; --i)
	{
		cout << cut[i];
		if (i) cout << " ";
	}
	cout << '\n';
 
	return 0;
}

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