Everything about multiset

///   ***   ---   |||         In the name of ALLAH        |||   ---   ***   ///



#include<bits/stdc++.h>
using namespace std;


typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef pair<int,int> pii;
typedef pair<double, double> pdd;
typedef pair<ll, ll> pll;
typedef vector<pii> vii;
typedef vector<pll> vll;
typedef double dl;

#define endl '\n'
#define PB push_back
#define F first
#define S second
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define sz(x) (int)x.size()

const double PI = acos(-1);
const double eps = 1e-9;
const int inf = 2000000000;
const ll infLL = 9000000000000000000;
#define MOD 1000000007

#define mem(a,b) memset(a, b, sizeof(a) )
#define sqr(a) ((a) * (a))

#define optimize() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define fraction() cout.unsetf(ios::floatfield); cout.precision(10); cout.setf(ios::fixed,ios::floatfield);
#define file() freopen("input.txt","r",stdin);freopen("output.txt","w",stdout);

#define dbg(args...) do {cerr << #args << " : "; faltu(args); } while(0)
void faltu () {            cerr << endl;}
template < typename T, typename ... hello>void faltu( T arg, const hello &... rest) {cerr << arg << ' ';faltu(rest...);}

ll gcd ( ll a, ll b ) { return __gcd ( a, b ); }
ll lcm ( ll a, ll b ) { return a * ( b / gcd ( a, b ) ); }

int main()
{
    optimize();

    /// Declare multiset
    multiset<int> s;

    /// insert in multiset.
    s.insert( 1 );
    s.insert( 4 );
    s.insert( 2 );
    s.insert( 2 );

    /// Print multiset size and its elements using for each loop
    cout << s.size() << endl; /// 4
    for ( auto u : s ) cout << u << " "; /// 1 2 2 4
    cout << endl;

    ///Print it elements using iterator
    set<int>::iterator it;
    for ( it = s.begin(); it != s.end(); it++ ) cout << *it << " "; /// 1 2 2 4
    cout << endl;

    /// element erase in multiset
    s.erase( 2 );
    cout << s.size() << endl; /// 2
    for ( auto u : s ) cout << u << " "; /// 1 4
    cout << endl;

    s.insert( 2 );
    s.insert( 2 );

    it = s.find( 2 );
    if ( it != s.end() ) s.erase( it );

    cout << s.size() << endl; /// 3
    for ( auto u : s ) cout << u << " "; /// 1 2 4
    cout << endl;

    s.erase( 5 );
    cout << s.size() << endl; /// 3
    for ( auto u : s ) cout << u << " "; /// 1 2 4
    cout << endl;

    /// another way of multiset declare and assigning a multiset into another
    multiset<int> tmp = { 6, 6, 1, 2, 3, 4, 5 };
    s = tmp;
    cout << s.size() << endl; /// 7
    for ( auto u : s ) cout << u << " "; /// 1 2 3 4 5 6 6
    cout << endl;

    /// Finding pointer where element 2 is located
    it = s.find( 2 );

    /// Checking is a element exist in multiset
    if ( it != s.end() ) cout << "Element exist\n";
    else cout << "Element not exist\n";

    /// Counting number of occurrence's of an element of multiset
    cout << s.count( 6 ) << endl; /// 2
    cout << s.count( 10 ) << endl; /// 0

    /// Checking is a multiset is empty of not
    cout << s.empty() << endl; /// 0

    /// Clearing full multiset
    s.clear();
    cout << s.empty() << endl; /// 1

    /// Printing smallest element in multiset
    s = tmp;
    cout << *s.begin() << endl; /// 1

    /// Printing largest element in a multiset
    cout << *(--s.end() ) << endl; /// 6
    cout << *s.rbegin() << endl; /// 6

    return 0;
}