C + + implementation of fast sorting algorithm

Quick Sort Basic Features

Complexity of Time: O (N*LGN)

Worst: O (n^2)

Space complexity: Best case: O (LGN), worst case: O (n), average condition: O (LGN)

Not stable.

About the space complexity of the quick sort, thank you @ fate his father. elaborate.

Quick sort because it takes up one space to return to the middle number each time recursion, the space complexity of one recursion is O (1).

The best case and worst-case recursive depth is O (LGN), and the corresponding space complexity is O (LGN)

At worst, the recursive depth is O (n), and the space complexity is O (n).

Algorithm

QUICKSORT (A, p, r)
    if p < R
       then Q←partition (A, p, r)   //Key
            QUICKSORT (A, p, q-1)
            QUICKSORT (A, q + 1, R)
     
PARTITION (A, P, R)
      X←a[r]
      i←p-1 for
      j←p to R-1 do if A[j]≤x then i←i
                 + 1
 exchange A[i] <-> a[j]
      exchange A[i + 1] <-> A[r] return
      i + 1

Example

Sorted Array: 7 3 5 9 8 5 1 10 4 6

A trip to the sequencing process analysis: