pytohn utils

def is_anagram(a: str, b:str):
  if len(a) != len(b): return False
  return ''.join(sorted(list(a))) == ''.join(sorted(list(b)))

def is_palindrome(a: str, b:str):
  return a[::-1] == b

def get_pow(a: int, b: int) -> int:
  if b == 1: return a
  if b == 0: return 1

  if b % 2 == 0:
    x = get_pow(a, b/2)
    return x * x
  return a * get_pow(a, b-1)

def get_pow_modulo(a: int, b: int, c: int) -> int:
  if b == 1: return a
  if b == 0: return 1

  if b % 2 == 0:
    x = get_pow(a, b/2, c)
    return ((x%c) * (x%c))%c
  return ((a%c) * (get_pow(a, b-1)%c))%c

def get_gcd(a: int, b: int) -> int:
  if a == 0: return b
  if b == 0: return a
  return get_gcd(b, a%b)

def get_lcm(a: int, b: int) -> int:
  return a*b // get_gcd(a, b)

def get_factorial(a: int) -> int:
  if a < 2: return 1
  return get_factorial(a-1) * a

def get_combination(n: int, r: int) -> int:
  n_r = n-r
  divisor = max(n_r, r)
  r = get_factorial(min(n_r, r))
  total = 1
  for i in range(divisor+1, n+1):
    gcd = get_gcd(i, r)
    total *= i//gcd
    if r == 1: continue
    r //= gcd
  return total

def get_permutation(n: int, r: int) -> int:
  total = 1
  for i in range(n-r+1, n+1):
    total *= i
  return total

def get_substring_index(haystack: str, needle: str, prime: int=101) -> int:
  # using rabin-karp
  H = len(haystack)
  N = len(needle)
  h = 0 # hash value for haystack
  n = 0 # hash value for needle
  d = 256 # number of characters in the input alphabet

  x = get_pow_modulo(256, N-1, prime)

  for i in range(N):
    n =
    h =

# get_substring_index("ASD", "asd"  )