Submission #978692

#	Time	Username	Problem	Language	Result	Execution time	Memory
978692		kunzaZa183	Feast (NOI19_feast)	C++17	100 / 100	177 ms	15328 KiB

feast

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 300001;
int arr[maxn];
int dp[maxn][2], counti[maxn][2]; // 0 = closed, 1 = open
int32_t main()
{
  cin.tie(0)->sync_with_stdio(0);
  cin.exceptions(cin.failbit);
  int n, k;
  cin >> n >> k;
  for (int i = 0; i < n; i++)
    cin >> arr[i];
  int l = 0, r = 1e18;
  while (l < r)
  {
    int cost = (l + r) / 2;
    memset(counti, 0, sizeof counti);
    memset(dp, 0, sizeof dp);
    for (int i = 0; i < n; i++)
    {
      dp[i + 1][0] = dp[i][0];
      counti[i + 1][0] = counti[i][0];

      if ((dp[i + 1][0] < dp[i][0] - cost + arr[i]) || (dp[i+1][0] == dp[i][0] - cost + arr[i] && counti[i+1][0] > counti[i][0] + 1))
      {
        dp[i + 1][0] = dp[i][0] - cost + arr[i];
        counti[i + 1][0] = counti[i][0] + 1;
      }

      if ((dp[i + 1][0] < dp[i][1] - cost + arr[i]) || (dp[i + 1][0] == dp[i][1] - cost + arr[i] && counti[i + 1][0] > counti[i][1] + 1))
      {
        dp[i + 1][0] = dp[i][1] - cost + arr[i];
        counti[i + 1][0] = counti[i][1] + 1;
      }

      dp[i + 1][1] = dp[i][0] + arr[i];
      counti[i + 1][1] = counti[i][0];

      if ((dp[i + 1][1] < dp[i][1] + arr[i]) || (dp[i + 1][1] == dp[i][1] + arr[i] && counti[i][1]<counti[i+1][1]))
      {
        dp[i + 1][1] = dp[i][1] + arr[i];
        counti[i + 1][1] = counti[i][1];
      }
    }
    if (counti[n][0] <= k)
      r = cost;
    else if (counti[n][0] > k)
      l = cost + 1;
  }
  int cost = l;
  for (int i = 0; i < n; i++)
  {
    dp[i + 1][0] = dp[i][0];
    counti[i + 1][0] = counti[i][0];

    if ((dp[i + 1][0] < dp[i][0] - cost + arr[i]) || (dp[i + 1][0] == dp[i][0] - cost + arr[i] && counti[i + 1][0] > counti[i][0] + 1))
    {
      dp[i + 1][0] = dp[i][0] - cost + arr[i];
      counti[i + 1][0] = counti[i][0] + 1;
    }

    if ((dp[i + 1][0] < dp[i][1] - cost + arr[i]) || (dp[i + 1][0] == dp[i][1] - cost + arr[i] && counti[i + 1][0] > counti[i][1] + 1))
    {
      dp[i + 1][0] = dp[i][1] - cost + arr[i];
      counti[i + 1][0] = counti[i][1] + 1;
    }

    dp[i + 1][1] = dp[i][0] + arr[i];
    counti[i + 1][1] = counti[i][0];

    if ((dp[i + 1][1] < dp[i][1] + arr[i]) || (dp[i + 1][1] == dp[i][1] + arr[i] && counti[i][1] < counti[i + 1][1]))
    {
      dp[i + 1][1] = dp[i][1] + arr[i];
      counti[i + 1][1] = counti[i][1];
    }
  }
  if (counti[n][0] <= k)
    r = cost;
  else if (counti[n][0] > k)
    l = cost + 1;
  cout << dp[n][0] + l * counti[n][0] << "\n";
}

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 20 / 20
• Subtask 7: 29 / 29