Finding the Smallest Index Difference of Repeated Primes

The function finds the smallest index difference of repeated elements in the list and returns it. If there are no repeated elements in the list, it returns None. The function first sorts the list, then uses binary search to determine the index of each prime number, and finally calculates the difference of the index list.

Technology Stack : bisect, collections.Counter, math.sqrt, sorted, bisect_left, bisect_right, Counter, find_diff, is_prime

Code Type : Function

Code Difficulty : Intermediate

                
                    
def aordiff(a_list):
    from bisect import bisect_left, bisect_right
    from collections import Counter
    from math import sqrt

    def find_diff(lst):
        count = Counter(lst)
        for key, value in count.items():
            if value > 1:
                return key
        return None

    def is_prime(n):
        if n <= 1:
            return False
        if n <= 3:
            return True
        if n % 2 == 0 or n % 3 == 0:
            return False
        i = 5
        while i * i <= n:
            if n % i == 0 or n % (i + 2) == 0:
                return False
            i += 6
        return True

    sorted_list = sorted(a_list)
    prime_indices = []
    for i in range(len(sorted_list)):
        if is_prime(sorted_list[i]):
            prime_indices.append(bisect_left(sorted_list, sorted_list[i]))

    diff = find_diff(prime_indices)
    return diff