AlgoDatSoSe25/schoeffelbe/pr03.py

import logging
logger = logging.getLogger(__name__)
# logging.basicConfig(level=logging.DEBUG)

import time

def timeMS(func, *args, **kwargs):
    startTime = time.perf_counter()
    result = func(*args, **kwargs)
    endTime = time.perf_counter()
    elapsedMS = (endTime - startTime) * 1000  # Convert to milliseconds
    print(f"{func.__name__} took {elapsedMS:.2f} ms")
    return result


from utils.memory_array import MemoryArray
from utils.memory_cell import MemoryCell
from utils.literal import Literal
from utils.constants import MIN_VALUE
from utils.memory_manager import MemoryManager
from utils.memory_range import mrange

def example():
    initial = [6, 5, 3, 8, 1, 7, 2, 4]
    # initial = [-6, -5, -3, -8, 1, 7, 2, 4]
    toSort = MemoryArray(initial)
    quickSortIterative(toSort, Literal(0), toSort.length().pred())
    logger.debug(f"sorted {toSort} vs initial {initial}")
    assert all(toSort[Literal(i)] == Literal(i+1) for i in range(len(initial))), "Array not sorted correctly"

    # analyze_complexity(quickSort, [10, 20, 30, 40, 50, 60, 70, 80, 90, 100])

def getPivot(z: MemoryArray, l: Literal, r: Literal, mode) -> Literal:
    if mode == 0:
        return r
    else:
        mid_offset = r.value - l.value
        mid_offset = mid_offset // 2
        mid = Literal(l.value + mid_offset)
    
        # Return median of left, middle, and right elements
        if ((z[l] <= z[mid] and z[mid] <= z[r]) or 
            (z[r] <= z[mid] and z[mid] <= z[l])):
            return mid
        elif ((z[mid] <= z[l] and z[l] <= z[r]) or 
              (z[r] <= z[l] and z[l] <= z[mid])):
            return l
        else:
            return r


def swap(z: MemoryArray, i: int, j: int):
    tmp = z[Literal(i)].value
    z[Literal(i)] = z[Literal(j)]
    z[Literal(j)].set(tmp)

# toSort[] --> Array to be sorted,
# left     --> Starting index,
# right    --> Ending index
# adapted from https://stackoverflow.com/questions/68524038/is-there-a-python-implementation-of-quicksort-without-recursion
def quickSortIterative(toSort : MemoryArray, left : Literal, right : Literal, mode=0):
    # Create a manually managed stack and avoid pythons recursion-limit
    size = right.value - left.value + 1
    stack : MemoryArray = MemoryArray([0] * size)
    top : MemoryCell = MemoryCell(-1)

    # push initial values of l and h to stack
    top += Literal(1)
    stack[top] = left
    top += Literal(1)
    stack[top] = right
  
    # Keep popping from stack until its empty
    while top >= Literal(0):
        logger.debug(f"size {size}, stack {stack}, right {right} and left {left}, top {top}") 

        # Pop h and l - Ensure we are not getting them by Ref, this will produce weird "JUST A LITTLE OF" Results
        right = Literal(stack[top].get())
        top -= Literal(1)
        left = Literal(stack[top].get())
        top -= Literal(1)
  
        # Set pivot element at its correct position in sorted array
        p = partitionIterative(toSort, left, right, mode)
  
        # If there are elements on left side of pivot, then push left side to stack
        if p.pred() > left:
            top += Literal(1)
            stack[top] = left
            top += Literal(1)
            stack[top] = p.pred()
  
        # If there are elements on right side of pivot, then push right side to stack
        if p.succ() < right:
            top += Literal(1)
            stack[top] = p.succ()
            top += Literal(1)
            stack[top] = right

def partitionIterative(arr : MemoryArray, l : Literal, h : Literal, mode=0):
    logger.debug(f"Partitioning {arr}, {l} and {h}")
    pivot_idx : Literal = getPivot(arr, l, h, mode)

    # If pivot isn't at the high end, swap it there
    if pivot_idx != h:
        swap(arr, int(pivot_idx), int(h))

    # Carefull that we do not use a reference. I suppose python would return one here if we just assign without value>Literal cast.
    # At least this helped fix weird issue
    pivotValue : Literal = arr[h]
    i : MemoryCell = MemoryCell(l.pred())
  
    for j in mrange(l, h):
        if arr[j] <= pivotValue:
            i += Literal(1)                 # increment index of smaller element
            swap(arr, int(i), int(j))
  
    swap(arr, i.succ().value, h.value)
    return i.succ()

def LEGACY_quickSort(z: MemoryArray, l: Literal = Literal(0), r: Literal = Literal(-1), mode=0):
    if r == Literal(-1):
        r = z.length().pred();
    if l < r:
        q = LEGACY_partition(z, l, r, mode)
        LEGACY_quickSort(z, l, q.pred())
        LEGACY_quickSort(z, q.succ(), r)

def LEGACY_partition(z: MemoryArray, l: Literal, r: Literal, mode):
    # Get pivot
    pivot_idx = getPivot(z, l, r, mode)
    
    # If pivot is not already at the right end, swap it there
    if pivot_idx != r:
        swap(z, int(pivot_idx), int(r))

    with MemoryCell(z[r]) as pivot, MemoryCell(l) as i, MemoryCell(r.pred()) as j:
        while i < j:
            while z[i] < pivot:
                i.set(i.succ())
            while j > l and z[j] >= pivot:
                j.set(j.pred())
            if i < j:
                swap(z, int(i), int(j))
                i.set(i.succ())
                j.set(j.pred())
        if i == j and z[i] < pivot:
            i.set(i.succ())
        if z[i] != pivot:
            swap(z, int(i), int(r))
        return Literal(i)


def analyze_complexity(fn, sizes):
    """
    Analysiert die Komplexität einer maximalen Teilfolgenfunktion.

    :param max_sequence_func: Die Funktion, die analysiert wird.
    :param sizes: Eine Liste von Eingabegrößen für die Analyse.
    """
    for size in sizes:
        MemoryManager.purge()  # Speicher zurücksetzen
        random_array = MemoryArray.create_random_array(size, -100, 100)
        fn(random_array, Literal(0), random_array.length().pred())
        MemoryManager.save_stats(size)

    MemoryManager.plot_stats(["cells", "adds", "compares", "reads", "writes"])


if __name__ == '__main__':
    # For debug, assert if working and complexity-analysis
    example()

    print("I ran into a MaxRecursionDepth Error. From what I read on the Internet python does not do Tailcall Optimizations")
    print("Increasing recursion-limit seems like a poor Idea, therefore tried an iterative approach with manual stack-keeping")

    toSort = MemoryArray.create_array_from_file("data/seq0.txt")
    print(toSort)
    quickSortIterative(toSort, Literal(0), toSort.length().pred())
    print(toSort)

    # analyze_complexity(quickSortIterative, [10, 20, 30, 40, 50, 60, 70, 80, 90, 100])
    for filename in ["data/seq0.txt", "data/seq1.txt", "data/seq2.txt" ,"data/seq3.txt"]:
    # for filename in [ "data/seq1.txt"]:
        print(filename)
        toSort = MemoryArray.create_array_from_file(filename)
        timeMS(quickSortIterative, toSort, Literal(0), toSort.length().pred(), mode=1)
        print(toSort)

    print("Kann durch die Modifikation eine besser Laufzeit als nlog(n) erreicht werden? Nein! nlog(n) ist das Minimum. Durch die Änderung kann aber der Worst-Case fall von n^2 für z.B. bereits vorsortierte Arrays oder Arrays mit vielen Duplikaten vermieden werden.")