Submission #6632975


Source Code Expand

#include <bits/stdc++.h>
#define int long long
#define pii pair<int,int>
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(c) (c).begin(),(c).end()
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
#define MINF(a) memset(a,0x3f,sizeof(a))
#define POW(n) (1LL<<(n))
#define IN(i,a,b) (a <= i && i <= b)
using namespace std;
template <typename T> inline bool CHMIN(T& a,T b) { if(a>b) { a=b; return 1; } return 0; }
template <typename T> inline bool CHMAX(T& a,T b) { if(a<b) { a=b; return 1; } return 0; }
template <typename T> inline void SORT(T& a) { sort(ALL(a)); }
template <typename T> inline void REV(T& a) { reverse(ALL(a)); }
template <typename T> inline void UNI(T& a) { sort(ALL(a)); a.erase(unique(ALL(a)),a.end()); }
template <typename T> inline T LB(vector<T>& v, T a) { return *lower_bound(ALL(v),a); }
template <typename T> inline int LBP(vector<T>& v, T a) { return lower_bound(ALL(v),a) - v.begin(); }
template <typename T> inline T UB(vector<T>& v, T a) { return *upper_bound(ALL(v),a); }
template <typename T> inline int UBP(vector<T>& v, T a) { return upper_bound(ALL(v),a) - v.begin(); }
template <typename T1, typename T2> ostream& operator<< (ostream& os, const pair<T1,T2>& p) { os << p.first << " " << p.second; return os; }
template <typename T1, typename T2> istream& operator>> (istream& is, pair<T1,T2>& p) { is >> p.first >> p.second; return is; }
template <typename T> ostream& operator<< (ostream& os, const vector<T>& v) { REP(i,v.size()) { if (i) os << " "; os << v[i]; } return os; }
template <typename T> istream& operator>> (istream& is, vector<T>& v) { for(T& in : v) is >> in; return is; }
template <typename T = int> vector<T> make_v(size_t a) { return vector<T>(a); }
template <typename T, typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...)); }
template <typename T, typename V> typename enable_if<is_class<T>::value == 0>::type fill_v(T &t, const V &v) { t = v; }
template <typename T, typename V> typename enable_if<is_class<T>::value != 0>::type fill_v(T &t, const V &v) { for(auto &e : t) fill_v(e,v); }
const int MOD = 1000000007;
const int INF = 0x3f3f3f3f3f3f3f3f;
const double EPS = 1e-10;

signed main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(10);

  int N,M;
  cin >> N >> M;
  vector<int> X(N);
  cin >> X;
  map<int,int> cnt;
  map<int, vector<int>> mp;
  for (int x : X) cnt[x]++;
  for (auto p : cnt) mp[p.first % M].push_back(p.second);
  for (auto&& p : mp) { SORT(p.second); REV(p.second); }
  int ans = 0;
  for (int i = 0; 2 * i <= M; i++) {
    if (i == 0 || 2 * i == M) {
      ans += accumulate(ALL(mp[i]), 0LL) / 2;
    } else {
      vector<int> &a = mp[i], &b = mp[M - i];
      int suma = accumulate(ALL(a), 0LL);
      int sumb = accumulate(ALL(b), 0LL);
      if (suma < sumb) {
        swap(suma, sumb);
        swap(a, b);
      }
      int rem = suma;
      for (int i = 0; i < a.size(); i++) {
        while (a[i] - 2 >= 0 && rem - 2 >= sumb) {
          a[i] -= 2;
          rem -= 2;
          ans++;
        }
      }
      ans += sumb;
    }
  }
  cout << ans << endl;

  return 0;
}

Submission Info

Submission Time
Task D - Pair Cards
User legosuke
Language C++14 (GCC 5.4.1)
Score 700
Code Size 3302 Byte
Status AC
Exec Time 101 ms
Memory 18176 KB

Judge Result

Set Name sample all
Score / Max Score 0 / 0 700 / 700
Status
AC × 2
AC × 34
Set Name Test Cases
sample sample-01.txt, sample-02.txt
all sample-01.txt, sample-02.txt, 01-01.txt, 01-02.txt, 01-03.txt, 01-04.txt, 01-05.txt, 01-06.txt, 01-07.txt, 01-08.txt, 01-09.txt, 01-10.txt, 01-11.txt, 01-12.txt, 01-13.txt, 01-14.txt, 01-15.txt, 01-16.txt, 01-17.txt, 01-18.txt, 01-19.txt, 01-20.txt, 01-21.txt, 01-22.txt, 01-23.txt, 01-24.txt, 01-25.txt, 01-26.txt, 01-27.txt, 01-28.txt, 01-29.txt, 01-30.txt, sample-01.txt, sample-02.txt
Case Name Status Exec Time Memory
01-01.txt AC 1 ms 256 KB
01-02.txt AC 39 ms 5628 KB
01-03.txt AC 39 ms 5584 KB
01-04.txt AC 40 ms 5632 KB
01-05.txt AC 40 ms 5632 KB
01-06.txt AC 40 ms 5760 KB
01-07.txt AC 41 ms 5760 KB
01-08.txt AC 43 ms 5760 KB
01-09.txt AC 45 ms 6016 KB
01-10.txt AC 60 ms 9472 KB
01-11.txt AC 79 ms 14848 KB
01-12.txt AC 9 ms 1024 KB
01-13.txt AC 18 ms 4480 KB
01-14.txt AC 51 ms 8316 KB
01-15.txt AC 51 ms 8320 KB
01-16.txt AC 53 ms 8576 KB
01-17.txt AC 59 ms 8320 KB
01-18.txt AC 58 ms 9088 KB
01-19.txt AC 63 ms 9728 KB
01-20.txt AC 101 ms 18176 KB
01-21.txt AC 18 ms 1280 KB
01-22.txt AC 18 ms 1408 KB
01-23.txt AC 18 ms 1408 KB
01-24.txt AC 19 ms 1408 KB
01-25.txt AC 23 ms 3712 KB
01-26.txt AC 36 ms 9216 KB
01-27.txt AC 51 ms 13184 KB
01-28.txt AC 20 ms 8448 KB
01-29.txt AC 8 ms 3456 KB
01-30.txt AC 22 ms 8064 KB
sample-01.txt AC 1 ms 256 KB
sample-02.txt AC 1 ms 256 KB