Submission #501807

#	Time	Username	Problem	Language	Result	Execution time	Memory
501807		600Mihnea	Fish (IOI08_fish)	C++17	16 / 100	3095 ms	25200 KiB

fish

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

struct Guy {
  int sz;
  int type;
};

bool operator < (Guy a, Guy b) {
  return a.sz < b.sz;
}

const int N = (int) 5e5 + 7;
int n, k, mod, pref[N];
Guy a[N];
vector<int> where[N];

int getCnt(int prefix, int type) {
  assert(0 <= prefix && prefix <= n);
  assert(1 <= type && type <= k);
  int sol = 0;
  int low = 0, high = (int) where[type].size() - 1;
  while (low <= high) {
    int mid = (low + high) / 2;
    if (where[type][mid] <= prefix) {
      sol = mid + 1;
      low = mid + 1;
    } else {
      high = mid - 1;
    }
  }
  return sol;
}

int solve() {
  int sol = 0;
  set<vector<int>> all;
  for (int mask = 1; mask < (1 << n); mask++) {
    vector<int> current;
    for (int i = 0; i < n; i++) {
      if (mask & (1 << i)) {
        current.push_back(i + 1);
      }
    }
    int sz = (int) current.size();
    if (sz >= 2) {
      bool ok = 1;
      ok &= (a[current[sz - 1]].sz >= 2 * a[current[sz - 2]].sz);
      if (!ok) {
        continue;
      }
    }
    vector<int> total;
    for (auto &x : current) {
      total.push_back(a[x].type);
    }
    sort(total.begin(), total.end());
    all.insert(total);
  }
  return (int) all.size();
}


int main() {
  ios::sync_with_stdio(0); cin.tie(0);

 /// freopen ("input", "r", stdin);

  cin >> n >> k >> mod;

  for (int i = 1; i <= n; i++) {
    cin >> a[i].sz >> a[i].type;
  }
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; i++) {
    where[a[i].type].push_back(i);
  }
  vector<int> potential;
  for (int i = 1; i <= k; i++) {
    assert(!where[i].empty());
    if (where[i].back() != n) {
      potential.push_back(where[i].back());
    }
  }

  {
    int pt = 0;
    for (int i = 1; i <= n; i++) {
      while (pt + 1 <= n && a[pt + 1].sz * 2 <= a[i].sz) {
        pt++;
      }
      assert(pt < i);
      pref[i] = pt;
    }
  }
  sort(potential.begin(), potential.end());
  assert((int) potential.size() == k - 1);
  int print = 0;

  {
    /// for the last one it is quite easy
    int sol = 1;
    for (int i = 1; i <= k; i++) {
      int frq = getCnt(pref[n], i);
      sol = sol * (ll) (frq + 1) % mod;
    }
    print += sol;
    if (print >= mod) {
      print -= mod;
    }
  }

  sort(potential.begin(), potential.end());
  assert((int) potential.size() == k - 1);

  for (int step = (int) potential.size() - 1; step >= 0; step--) {
    int ind = potential[step];
    if (getCnt(pref[ind], a[ind].type) + 1 <= getCnt(pref[n], a[ind].type)) {
      /// it is only useful when we cast smaller guys than him

      int sol = 1;
      for (int s = 0; s <= step; s++) {
        int frq = getCnt(pref[ind], a[potential[s]].type);
        sol = sol * (ll) (frq + 1) % mod;
      }
      print += sol;
      if (print >= mod) {
        print -= mod;
      }

    } else {
      /// et extra when Il y a maximum
      {

        int sol = 1;
        for (int s = 0; s < step; s++) {
          int frq = getCnt(pref[ind], a[potential[s]].type);
          sol = sol * (ll) (frq + 1) % mod;
        }
        {
          int frq = getCnt(pref[ind], a[potential[step]].type);
          sol = sol * (ll) frq % mod;
        }
        print += sol;
        if (print >= mod) {
          print -= mod;
        }

      }
      int sol = 1;
      for (int i = 1; i <= k; i++) {
        if (i == a[ind].type) {
          continue; /// no choice
        }
        int frq = getCnt(pref[ind], i);
        sol = sol * (ll) (frq + 1) % mod;
      }
      print += sol;
      if (print >= mod) {
        print -= mod;
      }
    }
  }
  cout << solve() % mod << "\n";
  exit(0);
  cout << print << "\n";
  return 0;
}

/**
: [1] [1,2] [2]
**/

Compilation message (stderr)

fish.cpp: In function 'int solve()':
fish.cpp:39:7: warning: unused variable 'sol' [-Wunused-variable]
   39 |   int sol = 0;
      |       ^~~

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