Submission #528445

#	Time	Username	Problem	Language	Result	Execution time	Memory
528445		WLZ	Let's Win the Election (JOI22_ho_t3)	C++14	100 / 100	57 ms	2304 KiB

Main

#include <bits/stdc++.h>
using namespace std;
 
const double INF = 1.0 / 0.0;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, k;
  cin >> n >> k;
  vector< pair<int, int> > states(n);
  for (int i = 0; i < n; i++) {
    cin >> states[i].second >> states[i].first;
    if (states[i].first == -1) states[i].first = 0x3f3f3f3f;
  }
  sort(states.begin(), states.end());

  auto solve = [&](int m) {
    vector< vector<double> > dp(n + 1, vector<double>(k - m + 1, INF));
    dp[0][0] = 0.0;
    for (int i = 0; i < n; i++) {
      for (int j = 0; j <= k - m; j++) {
        if (j < k - m) dp[i + 1][j + 1] = min(dp[i + 1][j + 1], dp[i][j] + (double) states[i].second / (m + 1));
        dp[i + 1][j] = min(dp[i + 1][j], dp[i][j] + (i - j >= m ? 0.0 : (double) states[i].first / (i - j + 1)));
      }
    }
    return dp[n][k - m];
  };

  int l = 0, r = k;
  while (l < r - 2) {
    //cout << l << ' ' << r << endl;
    int m1 = l + (r - l) / 3, m2 = r - (r - l) / 3;
    double x1 = solve(m1), x2 = solve(m2);
    if (x1 >= x2) l = m1;
    if (x1 <= x2) r = m2;
  }
  double ans = INF;
  for (int i = l; i <= r; i++) ans = min(ans, solve(i));
  cout << fixed << setprecision(10) << ans << '\n';
  return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 11 / 11
• Subtask 4: 12 / 12
• Subtask 5: 33 / 33
• Subtask 6: 11 / 11
• Subtask 7: 23 / 23