Submission #989278

#	Time	Username	Problem	Language	Result	Execution time	Memory
989278		OAleksa	Split the sequence (APIO14_sequence)	C++14	89 / 100	689 ms	111500 KiB

sequence

#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
const int N = 1e5 + 69;
const int K = 220;
int n, a[N], k, par[N][K];
long long dp[N], p[N];
struct line { 
  long long n, k;
  long long val(long long x) {
    return k * x + n;
  }
};
deque<pair<line, int>> dq[K];
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int tt = 1;
  //cin >> tt;
  while (tt--) {
    cin >> n >> k;
    for (int i = 1;i <= n;i++)
      cin >> a[i];
    for (int i = 1;i <= n;i++)
      p[i] = p[i - 1] + a[i];
    auto Get = [&](int l, int r) {
      return p[r] - p[l - 1];
    };
    for (int i = 1;i <= n;i++) 
      dp[i] = -1e18;
    dq[0].push_back({{0, 0}, 0});
    for (int j = 1;j <= k;j++) {
      for (int i = 1;i < n;i++) {
        if (j > i)
          continue;
        int x = p[n] - p[i], m = dq[j - 1].size();
        while (m > 1 && dq[j - 1][m - 1].f.val(x) <= dq[j - 1][m - 2].f.val(x)) {
          dq[j - 1].pop_back();
          --m;
        }
        dp[i] = dq[j - 1][m - 1].f.val(x) + p[i] * (p[n] - p[i]);
        par[i][j] = dq[j - 1][m - 1].s;
        line t = {dp[i], -p[i]};
        m = dq[j].size();
        while (m > 1 && (dq[j][0].f.k - t.k) * (dq[j][1].f.n - dq[j][0].f.n) >= (t.n - dq[j][0].f.n) * (dq[j][0].f.k - dq[j][1].f.k)) {
          dq[j].pop_front();
          --m;
        }
        dq[j].push_front({t, i});
      }
    }
    long long ans = 0;
    for (int i = 1;i < n;i++)
      ans = max(ans, dp[i]);
    vector<int> res;
    int t = -1;
    for (int i = 1;i < n;i++) {
      if (ans == dp[i])
        t = i;
    }
    assert(t != -1);
    while (t != 0) {
      res.push_back(t);
      t = par[t][k--];
    }
    cout << ans << '\n';
    reverse(res.begin(), res.end());
    for (auto j : res) 
      cout << j << ' ';
  }
  return 0; 
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:28:10: warning: variable 'Get' set but not used [-Wunused-but-set-variable]
   28 |     auto Get = [&](int l, int r) {
      |          ^~~

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