new_contents: # Link: https://oj.leetcode.com/problems/two-sum/
  
  class Solution:
      # @return a tuple, (index1, index2)
      def twoSum(self, num, target):
          """
          use hashtable
          """
          d = {}
          index1 = index2 = 0
          for i in range(0, len(num)):
              if (target - num[i]) in d:
                  index1 = d[target - num[i]]
                  index2 = i
                  break
              else:
                  d[num[i]] = i
          return (index1 + 1, index2 + 1)
  
subject: Add two-sum