AlgoDatSoSe24/SoSe24/lec03_sort_alg/merge_sort.py

from SoSe24.algodat.foundation import AlgoDatArray, AlgoDatValue, read_int_sequence
from time import perf_counter as pfc


def merge_sort(z: AlgoDatArray, buffer: AlgoDatArray, left: int, right: int):
    if left == right:
        return
    mid = (left + right) // 2
    merge_sort(z, buffer, left, mid)
    merge_sort(z, buffer, mid + 1, right)
    left_ptr = left
    right_ptr = mid+1
    storage_ptr = left
    while left_ptr <= mid or right_ptr <= right:
        if left_ptr <= mid and right_ptr <= right:
            if z[left_ptr] < z[right_ptr]:
                buffer[storage_ptr].value = z[left_ptr].value
                left_ptr += 1
                storage_ptr += 1
            else:
                buffer[storage_ptr].value = z[right_ptr].value
                right_ptr += 1
                storage_ptr += 1
        elif left_ptr <= mid:
            buffer[storage_ptr].value = z[left_ptr].value
            left_ptr += 1
            storage_ptr += 1
        else:
            buffer[storage_ptr].value = z[right_ptr].value
            right_ptr += 1
            storage_ptr += 1
    for i in range(left, right):
        z[i].value = buffer[i].value


if __name__ == "__main__":
    z = read_int_sequence("../../seq0.txt")
    print(z, len(z))
    start = pfc()
    storage = AlgoDatArray(z.size)  # buffer
    AlgoDatValue.summary()
    merge_sort(z, storage, 0, z.size-1)
    print(z)
    print(f"Dauer: {pfc() - start:.4f}s")
    AlgoDatValue.summary()