top_k_most_freq.cpp

#include <bits/stdc++.h>
using namespace  std;
#define vi vector<int>
#define pii pair<int,int>
#define vii vector<pii>
#define  rep(i,a,b) for(int i=a;i<b;i++)
#define ff first
#define ss second



int main(){

	int n,k;
	cin>>n>>k;
	vi a(n);

	rep(i,0,n){
		cin>>a[i];
	}

	map<int,int> freq;
	rep(i,0,n){
		int presentSize=freq.size();
		if(freq[a[i]]==0 && presentSize==k){
			break;
		}
	freq[a[i]]++;
	}

	vii ans;
	map<int ,int > :: iterator it;
	for ( it = freq.begin(); it!=freq.end(); it++)
	{
		if(it->ss !=0){

			pii p;
			p.ff=it->ss;
			p.ss=it->ff;
			ans.push_back(p);



		}
	}

	sort(ans.begin(),ans.end(),greater<pii>());
	vii:: iterator it1;

	for ( it1=ans.begin(); it1!=ans.end(); it1++)
	{
		cout<<it1->ss<<" "<<it1->ff<<endl;

	}
	cout<<endl;
	return 0;
}