Two Sum does not account for DUPs.

[JonPlusPlus]

In the current Two Sum solution, the Hash Map does not allow for duplicate numbers in the input array.

Working Example:
Input: nums = [3,2,4], target = 6 Output: [1,2]

• each output index points to a different value.

Broken Example:
Input: nums = [3,3], target = 6 Output should be: [0,1], but is: [0,0]

• when the Hash Map made a record of value '3', it could then record the duplicate '3' separately.

I suggest adding either:

• a method to populate the next available space,
• or a method to store multiple values under one key.