What type of algorithm is the Quicksort algorithm if it has random pivots?

Expert Solution

Lomuto's partition scheme or Hoare's partition scheme algorithm is use for the Quicksort algorithm if it has random pivots. In general, quicksort is a divide-and-conquer algorithm. It works by selecting a 'pivot' element from the array and partitioning the other elements into two sub-arrays.

Lomuto's Partition Scheme Algorithm using Random Pivots:

partition(arr[], lo, hi) 
    pivot = arr[hi]
    i = lo     
    for j := lo to hi – 1 do
        if arr[j] <= pivot then
            swap arr[i] with arr[j]
            i = i + 1
    swap arr[i] with arr[hi]
    return i

partition_r(arr[], lo, hi)
    r = Random Number from lo to hi
    Swap arr[r] and arr[hi]
    return partition(arr, lo, hi)

quicksort(arr[], lo, hi)
    if lo < hi
        p = partition_r(arr, lo, hi)
        quicksort(arr, lo , p-1)
        quicksort(arr, p+1, hi)

Lomuto's partition scheme is easy to implement as compared to Hoare scheme.

venereology answered 2 years ago

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