Introduction
In the mystical village of Coinholt, you stand behind the counter of your bakery, arranging a fresh batch of pastries.
The door creaks open, and in walks Denara, a skilled merchant with a keen eye for quality goods.
After a quick meal, she slides a shimmering coin across the counter, representing a value of 100 units.
You smile, taking the coin, and glance at the total cost of the meal: 88 units.
That means you need to return 12 units in change.
Denara holds out her hand expectantly.
“Just give me the fewest coins,” she says with a smile.
“My pouch is already full, and I don’t want to risk losing them on the road.”
You know you have a few options.
“We have Lumis (worth 10 units), Viras (worth 5 units), and Zenth (worth 2 units) available for change.”
You quickly calculate the possibilities in your head:
- one Lumis (1 × 10 units) + one Zenth (1 × 2 units) = 2 coins total
- two Viras (2 × 5 units) + one Zenth (1 × 2 units) = 3 coins total
- six Zenth (6 × 2 units) = 6 coins total
“The best choice is two coins: one Lumis and one Zenth,” you say, handing her the change.
Denara smiles, clearly impressed.
“As always, you’ve got it right.”
Instructions
Instructions
Determine the fewest number of coins to give a customer so that the sum of their values equals the correct amount of change.
Examples
- An amount of 15 with available coin values [1, 5, 10, 25, 100] should return one coin of value 5 and one coin of value 10, or [5, 10].
- An amount of 40 with available coin values [1, 5, 10, 25, 100] should return one coin of value 5, one coin of value 10, and one coin of value 25, or [5, 10, 25].
Source: Exercism ruby/change