Given an array, find the two indices that sum to a specific value.

Constraints

• Is there exactly one solution?
  • Yes
• Is there always a solution?
  • Yes
• Is the array an array of ints?
  • Yes
• Is the array sorted? No
• Are negative values possible?
  • Yes
• Can we assume the inputs are valid?
  • No
• Can we assume this fits memory?
  • Yes

Instructions:

• Program should be written in file build.py

• Function name should be two_sum.

• Input

   Type:  List, Integer
   Value: [9,12,5,1,13,18,-12,20,7], 16
  

• Expected Output

    Type:  List
    Value: [0,8]