37 lines
1.2 KiB
JavaScript
37 lines
1.2 KiB
JavaScript
const uuid = require('uuid')
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// Custom algorith for two cassettes. For three or more denominations, we'll need
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// to rethink this. Greedy algorithm fails to find *any* solution in some cases.
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// Dynamic programming may be too inefficient for large amounts.
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//
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// We can either require canononical denominations for 3+, or try to expand
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// this algorithm.
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exports.makeChange = function makeChange (cassettes, amount) {
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// Note: Everything here is converted to primitive numbers,
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// since they're all integers, well within JS number range,
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// and this is way more efficient in a tight loop.
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const small = cassettes[0]
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const large = cassettes[1]
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const largeDenom = large.denomination
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const smallDenom = small.denomination
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const largeBills = Math.min(large.count, Math.floor(amount / largeDenom))
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const amountNum = amount.toNumber()
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for (let i = largeBills; i >= 0; i--) {
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const remainder = amountNum - largeDenom * i
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if (remainder % smallDenom !== 0) continue
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const smallCount = remainder / smallDenom
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if (smallCount > small.count) continue
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return [
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{provisioned: smallCount, denomination: small.denomination, id: uuid.v4()},
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{provisioned: i, denomination: largeDenom, id: uuid.v4()}
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]
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}
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return null
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}
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