swmanstion_task_1.py

from typing import List, Any, Dict
from collections import Counter

"""
Write a function that receives two sequences: A and B of integers and returns one sequence C.
Sequence C should contain all elements from sequence A (maintaining the order) except those,
that are present in sequence B p times, where p is a prime number.
"""


def is_prime(n: int) -> bool:
    """
    O(n/2) -> O(n) coplexity
    """
    if n == 2 or n == 3: return True
    if n % 2 == 0 or n < 2: return False
    
    # only odd numbers. 
    # Internet says that you have to loop over up to sqrt(n) but I didnt dig 
    # in why it is true so played safe here and loop over up to n/2.
    for i in range(3, int(n / 2) + 1, 2):  
        if n % i == 0:
            return False

    return True


def get_prime_number_of_occurances_of_values_in_collection(collection: List[Any]) -> Dict[Any, bool]:
    values_count = dict(Counter(collection))

    result_dict = {}

    for key, value in values_count.items():
        if is_prime(value):
            result_dict[key] = True

    return result_dict


def combine_sequences(a: List[int], b: List[int]) -> List[int]:
    b_values_prime_number_count = get_prime_number_of_occurances_of_values_in_collection(b)
    result_collection = []

    for element in a:
        has_prime_number_count_int_b = b_values_prime_number_count.get(element, False)
        if not has_prime_number_count_int_b:
            result_collection.append(element)

    return result_collection


# tests assert
# initial tests
assert combine_sequences([1, 2], [1, 1, 1, 1, 2, 2]) == [1]
assert combine_sequences([-1, 2], [-1, -1, -1, -1, 2, 2]) == [-1]

# swmansion exaple:
A = [2, 3, 9, 2, 5, 1, 3, 7, 10]
B = [2, 1, 3, 4, 3, 10, 6, 6, 1, 7, 10, 10, 10]
C = [2, 9, 2, 5, 7, 10]
assert combine_sequences(A, B) == C