Submission #638661

#	Time	Username	Problem	Language	Result	Execution time	Memory
638661		Dec0Dedd	Table Tennis (info1cup20_tabletennis)	C++14	49 / 100	842 ms	309632 KiB

tabletennis

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

const int N = 2e5+10;
const int K = 50;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int rnd(int a, int b){ 
	return a+rng()%(b-a+1);
}

int a[N], n, k, sz;
gp_hash_table<int, int> cnt;
gp_hash_table<int, bool> m;

void add(int i) {
   for (int j=1; j<=sz; ++j) {
      if (j != i) ++cnt[a[i]+a[j]];
   }
}

int num(int s) {
   int res=0;
   for (int i=1; i<=sz; ++i) {
      if (2*a[i] == s || m.find(s-a[i]) == m.end()) continue;
      ++res;
   }
   return res;
}

vector<int> gen(int s) {
   vector<int> res;

   for (int i=1; i<=sz; ++i) {
      if (2*a[i] == s || m.find(s-a[i]) == m.end()) continue;
      res.push_back(a[i]);
   }
   return res;
} 

int main() {
   ios_base::sync_with_stdio(0);
   cin.tie(NULL);
   cout.tie(NULL);

   cin>>n>>k;
   sz=n+k;
   for (int i=1; i<=sz; ++i) cin>>a[i];
   for (int i=1; i<=sz; ++i) m[a[i]]=true;

   if (sz <= 2000) {
      for (int i=1; i<=sz; ++i) {
         for (int j=i+1; j<=sz; ++j) ++cnt[a[i]+a[j]];
      }
   } else {
      vector<int> r;
      for (int i=1; i<=sz; ++i) r.push_back(i);
      shuffle(r.begin(), r.end(), rng);

      for (int i=0; i<min(sz, K); ++i) add(r[i]);
   }
   vector<int> tmp;

   int mx=0;
   for (auto u : cnt) {
      if (u.second >= 18) tmp.push_back(u.first);
   }

   vector<int> x;
   for (auto u : tmp) {
      if (num(u) >= n) {
         x=gen(u);
         break;
      }
   }

   assert((int)x.size() >= n);
   for (auto u : x) cout<<u<<" ";
   cout<<"\n";
}

Compilation message (stderr)

tabletennis.cpp: In function 'int main()':
tabletennis.cpp:68:8: warning: unused variable 'mx' [-Wunused-variable]
   68 |    int mx=0;
      |        ^~

• Subtask 1: 11 / 11
• Subtask 2: 9 / 9
• Subtask 3: 14 / 14
• Subtask 4: 15 / 15
• Subtask 5: 0 / 9
• Subtask 6: 0 / 14
• Subtask 7: 0 / 15
• Subtask 8: 0 / 13