two_sum.py

# Solution
from typing import List


# from itertools import combinations
class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        dict_nums = {}
        for i, num in enumerate(nums):
            if target - num in dict_nums.keys():
                return [dict_nums[target - num], i]
            else:
                dict_nums[num] = i

# slower:

#  for (i, value_1), (j, value_2) in combinations(enumerate(nums), 2):
#      if value_1 + value_2 == target:
#          return [i, j]
#
#  return None


# Instantiation to check values
if __name__ == '__main__':
    Solve = Solution.twoSum(13, [2, 7, 11, 15], 9)  # [0,1]
    Solve_1 = Solution.twoSum(16, [3, 2, 3], 6)  # [0,2]
    Solve_2 = Solution.twoSum(23, [3, 2, 4], 6)  # [1,2]
    print(Solve)
    print(Solve_1)
    print(Solve_2)