Kth largest Element

/*
Logic:
Basically we have to find the Kth largest element in array of size n that will be the (n-k)th element if we
sort that array.
so,we will select an element for pivot(last element) and find it's actual position in sorted array.
using partition function and compare that position with k if same then that is our actual element else
we will check,
if k is in left of that position,pass the left array in partition else right.

*/

int partition(vector <int> &arr,int l,int r){
    int pivot=arr[r],i=l;
    for(int j=l;j<r;j++){  //it basically put all the smaller element than pivot in left and bigger in right.
        if(arr[j]<=pivot) swap(arr[j],arr[i++]);
    }
    swap(arr[i],arr[r]);   //put the pivot element at it's actual position.
    return i;              //return the acutal position of pivot element.
}
int fun(vector <int> &arr,int l,int r,int k){
        int i=partition(arr,l,r);
        if(i==k) return arr[i];
        else if(k<i){
            return fun(arr,l,i-1,k);
        }
        else{   //k>i
            return fun(arr,i+1,r,k);
        }
}
class Solution {
public:
    int findKthLargest(vector<int>& nums, int k) {
        return fun(nums,0,nums.size()-1,nums.size()-k);
    }
};