Submission #879644

#	Time	Username	Problem	Language	Result	Execution time	Memory
879644		mychecksedad	Let's Win the Election (JOI22_ho_t3)	C++17	10 / 100	4 ms	15192 KiB

Main

/* Author : Mychecksdead  */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
const int N = 1e3+100, M = 1e5+10, K = 52, MX = 30;


int n, k, sum[N][N];
array<int, 2> a[N];
pair<int, double> dp[N][N];

double get(int x, double y, double j){
  return y + x/j; 
}

void solve(){
  cin >> n >> k;
  for(int i = 1; i <= n; ++i){
    cin >> a[i][1] >> a[i][0];
    if(a[i][0] == -1) a[i][0] = MOD;
  }
  sort(a+1, a+1+n);

  sum[n+1][0] = 0;
  for(int i = n; i >= 1; --i){
    for(int j = 0; j < n - i + 1; ++j){
      sum[i][j] = min(sum[i + 1][j], j == 0 ? MOD : sum[i + 1][j - 1] + a[i][1]);
    }
    sum[i][n - i + 1] = sum[i + 1][n - i] + a[i][1];
  }
  double ans = sum[1][k];

  for(int i = 0; i <= n; ++i) for(int j = 0; j <= n; ++j) dp[i][j] = {MOD, MOD};
  dp[0][0] = {0, 0};
  for(int i = 1; i <= k; ++i){
    dp[i][0] = dp[i - 1][0];
    dp[i][0].first += a[i][1];
    for(int j = 1; j <= i; ++j){
      double val1 = get(dp[i - 1][j].first + a[i][1], dp[i - 1][j].second, j + 1);
      double val2 = get(dp[i - 1][j - 1].first, dp[i - 1][j - 1].second + a[i][0] / (double) j, j + 1);
      if(val1 <= val2){
        dp[i][j] = {dp[i - 1][j].first + a[i][1], dp[i - 1][j].second};
      }else{
        dp[i][j] = {dp[i - 1][j - 1].first, dp[i - 1][j - 1].second + a[i][0] / (double) j};
      }
      ans = min(ans, get(sum[i + 1][k - i] + dp[i][j].first, dp[i][j].second, j + 1));
    }
  }
  cout << fixed << setprecision(5);
  cout << ans;
}


int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int tt = 1, aa;
  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);
  while(tt--){
    solve();
    en;
  }
  cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
  return 0;
} 

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:61:15: warning: unused variable 'aa' [-Wunused-variable]
   61 |   int tt = 1, aa;
      |               ^~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 0 / 11
• Subtask 4: 0 / 12
• Subtask 5: 0 / 33
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23