Submission #241058

#	Time	Username	Problem	Language	Result	Execution time	Memory
241058		Nightlight	Split the sequence (APIO14_sequence)	C++14	100 / 100	1333 ms	80760 KiB

sequence

#include <bits/stdc++.h>
using namespace std;

int N, K;
long long pre[100001];
long long dp[2][100001];
int opt[201][100001];

long long cost(int l, int r) {
  return pre[l - 1] * (pre[r] - pre[l - 1]);
}

void dnc(int k, int l, int r, int kl, int kr) {
  if(l > r) return;
  long long best = -1e18, bestid = 0;
  int mid = (l + r) >> 1;
  int skg = k & 1;
  for(int i = kl; i <= mid && i <= kr; i++) {
    long long now = dp[!skg][i - 1] + cost(i, mid);
    if(now > best) {
      bestid = i;
      best = now;
    }
  }
  opt[k][mid] = bestid - 1;
  dp[skg][mid] = best;
  dnc(k, l, mid - 1, kl, bestid);
  dnc(k, mid + 1, r, bestid, kr);
}

int main() {
  scanf("%d %d", &N, &K);
  K++;
  for(int i = 1; i <= N; i++) {
    scanf("%lld", &pre[i]);
    pre[i] += pre[i - 1];
  }
  for(int i = 2; i <= K; i++) {
    dnc(i, i, N, i, N);
  }
  printf("%lld\n", dp[K & 1][N]);
  int now = N;
  vector<int> ans;
  for(int i = K; i > 1; i--) {
    now = opt[i][now];
    ans.push_back(now);
  }
  for(int i = ans.size() - 1; i >= 0; i--) printf("%d ", ans[i]);
  puts("");
  cin >> N;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:32:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &N, &K);
   ~~~~~^~~~~~~~~~~~~~~~~
sequence.cpp:35:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld", &pre[i]);
     ~~~~~^~~~~~~~~~~~~~~~~

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