Submission #37892

#	Time	Username	Problem	Language	Result	Execution time	Memory
37892		MatheusLealV	Split the sequence (APIO14_sequence)	C++14	71 / 100	2000 ms	89248 KiB

sequence

#include <bits/stdc++.h>
#define N 100005
#define K 202
#define inf 2000000000000000
#define f first
#define s second
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pii;

int n, k, r, block[N], qtd, prox[N][K];

ll dp[N][3], sum[N];

vector< pair<pii, int> > line;

inline ll F(ll x, int id)
{
	return line[id].f.f*x + line[id].f.s;
}
inline double intersect(pii r, pii s)
{
  return ((double)(r.s - s.s))/((double)(s.f - r.f));
}

inline bool bad(pii A, pii B, pii C)
{
  return intersect(A, C) > intersect(B, A);
}

inline void addline(pair<pii, int> l)
{
	if(line.size() && line.back().f.f == l.f.f)
	{
		if(line.back().f.s < l.f.s) return;

		if(line.back().f.s == l.f.s && line.back().s < l.s) return;

		line.pop_back();

		line.push_back(l);

		return;
	}

	while(line.size() >= 2 && bad( line[line.size() - 2].f, line.back().f, l.f )) line.pop_back();

	line.push_back(l);
}

inline pii query(int x)
{
	pii best = pii(inf, -1);
	int p = line.size();
	if(r >= p) r = p - 1;
	while(r < p - 1 && F(x, r) > F(x, r + 1))r++;
	return pii(F(x, r), line[r].s);
}

inline void print(int ini, int k)
{
	while(true)
	{
		if(!prox[ini][k]) return;

		qtd ++;

		block[prox[ini][k]] = 1;

		cout<<prox[ini][k]<<" ";

		ini = prox[ini][k] + 1;
		
		k --;
	}
}

int32_t main()
{
	ios::sync_with_stdio(false); cin.tie(0);

	cin>>n>>k;

	for(int i = 1; i <= n; i++) cin>>sum[i], sum[i] += sum[i - 1];

	for(int i = 0; i <= n; i++) dp[i][0] = 0;

	for(int i = 0; i <= k; i++) dp[n][i] = 0;

	for(int q = 1; q <= k ; q++)
	{
		for(int i = n - 1; i >= 1; i--)
		{
			addline(make_pair(pii( -sum[i], -(sum[i]*sum[n] - sum[i]*sum[i] + dp[i + 1][ (q + 1)%2 ] )), i));

			pii best = query(sum[i - 1]);

			dp[i][q%2] = -best.f - sum[i - 1]*sum[n];

			prox[i][q] = best.s;
		}

		line.clear();

		//r = 0;
	}

	cout<<dp[1][k%2]<<"\n";

	print(1, k);

	int extra = k - qtd;

	for(int i = 1, cnt = 0; i <= n && cnt < extra; i++)
	{
		if(!block[i]) cout<<i<<" ", cnt ++;
	}

	cout<<"\n";
}

Compilation message (stderr)

sequence.cpp: In function 'pii query(int)':
sequence.cpp:53:6: warning: variable 'best' set but not used [-Wunused-but-set-variable]
  pii best = pii(inf, -1);
      ^

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