from datetime import datetime

epoch_time = 1753823646  # Example epoch time (March 15, 2023 00:00:00 UTC)

# Convert epoch time to a UTC datetime object
utc_datetime = datetime.utcfromtimestamp(epoch_time)

print(f"Epoch time: {epoch_time}")
print(f"UTC datetime: {utc_datetime}")

# You can also format the output string
formatted_utc_time = utc_datetime.strftime('%m-%d-%Y %H:%M:%S UTC')
print(f"Formatted UTC datetime: {formatted_utc_time}")

from collections import defaultdict

def collect_dictionary(obj):
  inv_obj = defaultdict(list)
  for key, value in obj.items():
    inv_obj[value].append(key)
  return dict(inv_obj)
  
ages = {
  'Peter': 10,
  'Isabel': 10,
  'Anna': 9,
}
collect_dictionary(ages) # { 10: ['Peter', 'Isabel'], 9: ['Anna'] }

# @return a list of strings, [s1, s2]
def letterCombinations(self, digits):
    if '' == digits: return []
    kvmaps = {
        '2': 'abc',
        '3': 'def',
        '4': 'ghi',
        '5': 'jkl',
        '6': 'mno',
        '7': 'pqrs',
        '8': 'tuv',
        '9': 'wxyz'
    }
    return reduce(lambda acc, digit: [x + y for x in acc for y in kvmaps[digit]], digits, [''])

def clamp_number(num, a, b):
  return max(min(num, max(a, b)), min(a, b))
  
clamp_number(2, 3, 5) # 3
clamp_number(1, -1, -5) # -1

# Deleting all even numbers from a list
a = [1,2,3,4,5]
del a[1::2]
print(a)

def check_prop(fn, prop):
  return lambda obj: fn(obj[prop])
  
check_age = check_prop(lambda x: x >= 18, 'age')
user = {'name': 'Mark', 'age': 18}
check_age(user) # True