This is a coding problem that I solved. See below for the coding problem description.
You are a given a set of stones, each of which has a weight, like 3 lbs or 7 lbs.
You will now smash the stones together from biggest to smallest such that you take 2 stones and smash them.
Continue until there is only 1 stone left.
Determine what the weight of the last stone is given the following conditions:
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Always smash the biggest 2 stones together.
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If the you smash a bigger stone with a smaller stone, then you get a stone that is the difference in weight: a 7 lb. and 3 lb. stone smashed together creates a 4 lb. stone.
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If you smash stones that are the same weight, then both stones are obliterated. For example, smash two 4 lb. stones and you get 0 remaining stones.
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Assume that the stones you are given are not sorted by weight.
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Find the last stone weight with method lastStoneWeight(weights)
- You have 5 stones of the following weights: [3, 4, 4, 7, 1]
- First we'll smash 7 & 4 stones, which leads to [3, 4, 3, 1]
- Next we'll smash 4 & 3 stones, which leads to [1, 3, 1]
- Next we'll smash 3 & 1 stones, which leads to [2, 1]
- Finally we'll smash 2 & 1 stones, which leads to [1]
The weight of the last stone after all stones are smashed together is 1.
- You have 5 stones of the following weights: [10, 10, 5, 1, 1]
- First smash 10 and 10: [5, 1, 1]
- Next smash 5 and 1: [4, 1]
- Finally smash 4 and 1: [3]
The weight of the last stone is 3.
Tests are located in 5 files currently:
- lastStoneWeight.rb
- binary_search_plus.rb
- smash_stones_operator.rb
- weight_store_tracker.rb
- weight_set.rb
You can run the tests with:
rspec lastStoneWeight.rbrspec binary_search_plus.rbrspec smash_stones_operator.rbrspec weight_store_tracker.rbrspec weight_set.rb
Please note that because all files are required in lastStoneWeight.rb, you can run all tests with simply rspec lastStoneWeight.rb.