Submission #624150

#	Time	Username	Problem	Language	Result	Execution time	Memory
624150		slime	Let's Win the Election (JOI22_ho_t3)	C++14	10 / 100	918 ms	993876 KiB

Main

#include "bits/stdc++.h"
using namespace std;
#define int long long
const int MAXN = 3e5 + 10;
const int MOD = 998244353;
#define ll __int128
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
  int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
ll read() { int x; cin >> x; return (ll)x; }
long long bm(long long b, long long p) {
  if(p==0) return 1 % MOD;
  long long r = bm(b, p >> 1);
  if(p&1) return (((r*r) % MOD) * b) % MOD;
  return (r*r) % MOD;
}
long long inv(long long b) { 
  return bm(b, MOD-2);
}
long long f[MAXN];
long long nCr(int n, int r) { 
  long long ans = f[n]; ans *= inv(f[r]); ans %= MOD;
  ans *= inv(f[n-r]); ans %= MOD; return ans;
}
long long fib[MAXN], lucas[MAXN];
void precomp() { 
  for(int i=0; i<MAXN; i++) f[i] = (i == 0 ? 1 % MOD : (f[i-1] * i) % MOD); 
  lucas[0] = 2;
  lucas[1] = 1;
  for(int i=2; i<MAXN; i++) lucas[i] = (lucas[i-2] + lucas[i-1]) % MOD;
  fib[0] = 0;
  fib[1] = 1;
  for(int i=2; i<MAXN; i++) fib[i] = (fib[i-2] + fib[i-1]) % MOD;
}
int fastlog(int x) {
  return (x == 0 ? -1 : 64 - __builtin_clzll(x) - 1);
}
void google(int i) { cout << "Case #" << i << ": "; }
int csb(int l, int r, int k) { // count number of [l, r] such that i & 2^k > 0
  if(l > r) return 0;
  if(l == 0) {
    int s = r / (1ll << (k+1)); // number of complete cycles
    int t = r % (1ll << (k+1));
    int ans = s * (1ll << k);
    ans += (t >= (1ll << k) ? t - (1ll << k) + 1 : 0);
    return ans;
  }
  else return csb(0, r, k) - csb(0, l - 1, k);
}
int lis(vector<int> a) {
  int n = a.size();
  int bucket[n+1];
  for(int i=1; i<=n; i++) bucket[i] = 1e18;
  int ans = 1;
  for(int x: a) {
    auto it = lower_bound(bucket + 1, bucket +n +1, x);
    int d = distance(bucket, it);
    ans = max(ans, d);
    bucket[d] = min(bucket[d], x);
  }
  return ans;
}
bool cmp(pair<int, int> x, pair<int, int> y) {
  if(x.second == y.second) return x.first < y.first;
  return x.second < y.second;
}
void solve(int tc) {
  int n, k;
  cin >> n >> k;
  int a[n+1], b[n+1];
  pair<int, int> p[n+1];
  for(int i=1; i<=n; i++) {
    cin >> p[i].first >> p[i].second;
    if(p[i].second == -1) p[i].second = 1226;
  }
  sort(p+1, p+n+1, cmp);
  for(int i=1; i<=n; i++) a[i] = p[i].first, b[i] = p[i].second;


  double dp[k+1][n+2][n+1];
  for(int i=0; i<=k; i++) for(int j=0; j<n+2; j++) for(int l=0; l<n+1; l++) dp[i][j][l] = 1e18;
  dp[0][1][0] = 0;
  for(int i=1; i<=k; i++) {
    for(int j=1; j<=n+1; j++) {
      for(int l=1; l<=n; l++) {
        // include l, 'A'
        dp[i][j][l] = dp[i-1][j][l-1] + a[l] * 1.0 / j;
        // include l, 'B'
        if(b[l] != 1226 && j > 1) dp[i][j][l] = min(dp[i][j][l], dp[i-1][j-1][l-1] + b[l] * 1.0 / (j-1));
        // don't include l
        dp[i][j][l] = min(dp[i][j][l], dp[i][j][l-1]);
      }
    }
  }
  double ans = 1e18;
  for(int i=1; i<=n+1; i++) ans = min(ans, dp[k][i][n]);
  cout << fixed << setprecision(6) << ans << "\n";

} 
int32_t main() {
  precomp();
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
}
// I don't know geometry.
// Teaming is unfair.

/*
7
5
31 33 (2)
19 27 (8)
28 36 (8)
38 51 (13)
20 35 (15)
25 56 (31)
11 57 (46)

7
5
19 27
31 33
20 35
28 36
38 51
25 56
11 57

optimal order:
7
5
19 27
31 33
28 36
38 51
25 56
11 57
20 35
*/

• 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