k-largest element

 

You are given with an integer k and an array of integers that contain numbers in random order. You have to find k largest numbers from given array. You need to save them in an array and return it.

Note:

1. Time complexity should be O(n * logk) and space complexity should not be more than O(k).
2. Order of elements in the output is not important.

Input Format:

The first line of input contains an integer, that denotes the value of the size of the array. Let us denote it with the symbol N.
The following line contains N space separated integers, that denote the value of the elements of the array.
The following contains an integer, that denotes the value of k.

Output Format :

The first and only line of output contains k largest elements.

Constraints:

Time Limit: 1 sec

Sample Input 1:

13
2 12 9 16 10 5 3 20 25 11 1 8 6 
4

Sample Output 1:

12 16 20 25

#include<bits/stdc++.h>
using namespace std;
vector<int> kLargest(int arr[], int n, int k) {
    // Write your code here
    priority_queue<int>pq;
    vector<int>ans;
   
   for(int i=0;i<n;i++)
   pq.push(arr[i]);
   for(int i=0;i<k;i++){
       ans.push_back(pq.top());
       pq.pop();
   }
   return ans;
}