Submission #624252

#	Time	Username	Problem	Language	Result	Execution time	Memory
624252		slime	Let's Win the Election (JOI22_ho_t3)	C++14	66 / 100	2577 ms	254536 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) {
  return x.second < y.second;
}
int n, k, a[MAXN], b[MAXN];
double fun(int bcnt) {
  double dp[k - bcnt + 1][bcnt + 1][n + 1]; // type A, type B, prefix
  for(int i=0; i<=k-bcnt; i++) {
    for(int j=0; j<=bcnt; j++) {
      for(int l=0; l<=n; l++) {
        dp[i][j][l] = 1e18;
      }
    }
  }
  for(int i=0; i<=n; i++) dp[0][0][i] = 0;
  for(int i=0; i<=k-bcnt; i++) {
    for(int j=0; j<=bcnt; j++) {
      if(i == 0 && j == 0) continue;
      for(int l=1; l<=n; l++) {
        // register as type A
        if(i > 0) dp[i][j][l] = dp[i-1][j][l-1] + a[l] * 1.0 / (bcnt + 1);
        // register as type B
        if(j > 0 && b[l] != 1226) dp[i][j][l] = min(dp[i][j][l], dp[i][j-1][l-1] + b[l] * 1.0 / j);
        // register as neither
        dp[i][j][l] = min(dp[i][j][l], dp[i][j][l-1]);
      }
    }
  }
  return dp[k-bcnt][bcnt][n];
}
void solve(int tc) {
  cin >> n >> k;
  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;
  }
  int lb = 0, rb = k;
  while(lb < rb) {
    int mid = (lb + rb) >> 1;
    if(fun(mid) > fun(mid+1)) lb = mid+1;
    else rb = mid;
  }
  cout << fixed << setprecision(10) << fun(lb) << "\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.
 
/*
8
7
3 15
19 40
11 62
7 72
16 27
33 53
14 50
17 24
*/

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