Find the k-th smallest element

1001. Find the k-th smallest element   

Given a sequence A=(a1,...,an), your job is to find the (k+1)-th smallest element of A.

For example, A=(3, 2, 3, 4, 5) and k=1, then 3 is returned, since 3 is the second smallest element of A.

Please implement and submit the following function:

int select(int a[], int n, int k) {

  // Your code will be here. You may invoke other functions.

}

Note: 0<=k<n<=1000000

int select(int a[], int n, int k , int l = 0 ) {
int pivot = a[l] ;
int left = l + 1 , right = n - 1 ;
while(left <= right){
while(a[left] <= pivot){
if(left > right) break ;
left ++ ;
}
while(a[right] > pivot){
if(left > right) break ;
right -- ;
}
if(left > right) break ;
swap(a[right] , a[left]) ;
}
swap(a[right] , a[l]) ;
if(k == right) return a[right] ;
if(k < right){
return select(a , right , k , l) ;
}else{
return select(a , n, k , right + 1) ;
}
}