Sherlock_and_Anagrams.py

# https://www.hackerrank.com/challenges/sherlock-and-anagrams/problem

def sherlockAndAnagrams(s):
    from collections import defaultdict
    from math import factorial

    # Creating a dictionary of anagrams:
    dictionary = defaultdict(lambda: 0)
    for i in range(len(s)):
        for j in range(i + 1, len(s) + 1):
            sorted_sequence = sorted(list(s[i:j]))
            dictionary["".join(sorted_sequence)] += 1
    
    # Calculating and adding the number of combinations per anagram-item:
    combinations = 0
    for item, value in dictionary.items():
        if value >= 2:
            combinations += factorial(value) // (2 * factorial(value - 2))

    return combinations