Submission #994109


Source Code Expand

#include <bits/stdc++.h>
#define int long long
#define range(i,x,y) i=(x);i<(y);i++
#define rep(i,n) for(int i=0,i##_len=n;i<i##_len;i++)
#define all(x) begin(x),end(x)
#define lim(x,r,l) (r<=x&&x<l)
typedef long long ll;
typedef long double ld;
using namespace std;


int solve(multiset<int> a, multiset<int> b){
  int aod = 0, bod = 0;
  for(auto aa: a) {
    //cout <<"a" <<  aa ;
    if(aa % 2 == 1) aod++;
  }
  for(auto bb: b){
    //cout <<"b" <<  bb;
    if(bb % 2 == 1) bod++;
  }
//  cout <<endl;

  if(aod > bod){
    swap(aod, bod); swap(a, b);
  }
  //aod <= bod

  int bipaired = aod;

  multiset<int> ca, cb, ccb;
  for(auto aa : a){
    ca.insert(aa/2*2);
  }

  int suma = 0;
  for(auto aa: ca){
    suma += aa;
  }//cout << endl;

  int tmpb = bipaired;
  //cout <<"B"; for(auto bb:b)cout <<bb <<","; cout << endl;
  for(auto& bb : b){
    if(tmpb > 0 && bb%2==1) {
      cb.insert(bb-1);
      tmpb--;
    }else{
      cb.insert(bb);
    }
  }
  //cout <<"CB"; for(auto bb:cb)cout <<bb <<","; cout << endl;

  int bpar = 0;
  //cout << suma << endl;
  for(auto& bb : cb){
    if(suma > 0 && bb%2==1) {
      ccb.insert(bb-1);
      suma--;
      bpar ++;
    }else{
      ccb.insert(bb);
    }
  }

  //cout <<"CCB"; for(auto bb:ccb)cout <<bb <<","; cout << endl;

  int res = 0;
  for(auto bb: ccb){
    res += bb / 2;
  }

  //cout << bipaired << "," << suma << "B" << bpar << endl;
  //cout << "R" << res << endl;

  return bipaired + (suma / 2) + res + bpar;
}
/*
signed main(){
  int n, m; cin >> n >> m;
  multiset<int> a, b;
  rep(i,n) {int aa; cin >> aa; a.insert(aa);}
  rep(i,m) {int bb; cin >> bb; b.insert(bb);}
  cout << "RES" << solve(a, b) << endl;
  return 0;
}
*/
signed main(){
  int n, m; cin >> n >> m;
  vector<int> x(n);
  vector<map<int,int>> mods(m, map<int,int>());

  rep(i, n){
    int xx; cin >> xx;
    x[i] = xx;
    auto& mm = mods[xx%m];
    if(mm.count(xx) == 0){
      mm[xx] = 1;
    }else{
      mm[xx]++;
    }
  }
  vector<multiset<int>> modn(m, multiset<int>());
  rep(i, m){
    for(auto kv : mods[i]){
      int num, cnt; tie(num, cnt) = kv;
      modn[i].insert(cnt);
    }
  }
  int res = 0;
  {
    int ss = 0;
    for(auto aa: modn[0]) ss += aa;
    res += ss/2;
  }
  if(m % 2 == 0){
    int ss = 0;
    for(auto aa: modn[m/2]) ss += aa;
    res += ss/2;
  }

  //cout << "PRE" << res << endl;

  rep(i, (m - 1) / 2){
    res += solve(modn[i + 1], modn[m - i - 1]);
  }
  cout << res << endl;
}

Submission Info

Submission Time
Task D - Pair Cards
User wass80
Language C++14 (GCC 5.4.1)
Score 700
Code Size 2587 Byte
Status AC
Exec Time 119 ms
Memory 21376 KB

Judge Result

Set Name sample all
Score / Max Score 0 / 0 700 / 700
Status
AC × 2
AC × 32
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
Case Name Status Exec Time Memory
01-01.txt AC 2 ms 256 KB
01-02.txt AC 84 ms 7936 KB
01-03.txt AC 82 ms 7936 KB
01-04.txt AC 96 ms 12928 KB
01-05.txt AC 93 ms 11648 KB
01-06.txt AC 90 ms 9344 KB
01-07.txt AC 87 ms 8448 KB
01-08.txt AC 77 ms 8064 KB
01-09.txt AC 78 ms 8064 KB
01-10.txt AC 66 ms 11648 KB
01-11.txt AC 71 ms 17280 KB
01-12.txt AC 32 ms 1024 KB
01-13.txt AC 39 ms 5120 KB
01-14.txt AC 99 ms 11904 KB
01-15.txt AC 119 ms 16640 KB
01-16.txt AC 107 ms 12416 KB
01-17.txt AC 95 ms 12032 KB
01-18.txt AC 86 ms 12288 KB
01-19.txt AC 79 ms 13184 KB
01-20.txt AC 83 ms 21376 KB
01-21.txt AC 49 ms 1408 KB
01-22.txt AC 48 ms 1536 KB
01-23.txt AC 42 ms 1536 KB
01-24.txt AC 38 ms 1536 KB
01-25.txt AC 39 ms 4352 KB
01-26.txt AC 47 ms 10752 KB
01-27.txt AC 48 ms 15488 KB
01-28.txt AC 17 ms 9984 KB
01-29.txt AC 8 ms 3968 KB
01-30.txt AC 15 ms 9600 KB
sample-01.txt AC 3 ms 256 KB
sample-02.txt AC 3 ms 256 KB