Coin Co-Operation

Let's say that there exists a machine that gives out free coins, but with a twist!

Separating two people is a wall, and this machine is placed in such a way that both people are able to access it. Spending a coin in this machine will give the person on the other side 3 coins and vice versa.

If both people continually spend coins for each other (SHARING), then they'll both gain a net profit of 2 coins per turn. However, there is always the possibility for someone to act selfishly (STEALING): they spend no coins, yet they still receive the generous 3 coin gift from the other person!

Here's an example of Red taking advantage of Green!

The Challenge

Assuming that both people start with 3 coins each, create a function that calculates both people's final number of coins. You will be given two arrays of strings, with each string being the words "share" or "steal".

Examples

getCoinBalances(["share"], ["share"]) ➞ [5, 5]
// Both people spend one coin, and receive 3 coins each.

getCoinBalances(["steal"], ["share"]) ➞ [6, 2]
// Person 1 gains 3 coins, while person 2 loses a coin.

getCoinBalances(["steal"], ["steal"]) ➞ [3, 3]
// Neither person spends any coins and so no one gets rewarded.

getCoinBalances(["share", "share", "share"], ["steal", "share", "steal"]) ➞ [3, 11]

Notes

• No tests will include a negative number of coins.
• All words will be given in lowercase.