127B - Canvas Frames - CodeForces Solution

#include <bits/stdc++.h>

using namespace std;

void Mon_on_da_code() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
}


#define ll long long
#define   endl         "\n"
#define   lpi(n)       for(int i=0 ; i<(n) ; i++)
#define   lpj(n)       for(int j=0 ; j<(n) ; j++)
#define   all(v)      ((v).begin()),((v).end())
#define   allr(v)      ((v).rbegin()),((v).rend())
#define   pb           push_back
#define F first
#define S second
#define sz(x) int((x).size())
#define ui unsigned int
typedef vector<int> vi;
typedef vector<ll> vll;

void flow() {
    int n,q;
    int Freq1[101] = {0};
    cin>>n;
    lpi(n) cin>>q , Freq1[q]++;
    double st{};
    lpi(101){
        if(Freq1[i]>=4) {
            st += Freq1[i] / 4;
            Freq1[i] = Freq1[i] % 4;
        }
        if(Freq1[i]>1 and Freq1[i]<=3)
            st+=0.5;
    }
    cout<<int(st);


}

int main() {
    Mon_on_da_code();
    int tt = 1;
    //  cin >> tt;
    while (tt--) {
        flow();
    }
    return 0;
}