2023-05-01 16:16:48 +10:00
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/**
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* @author mrmagic2020
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* @description The function will find the parity outlier from an array of integers.
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* @see https://en.wikipedia.org/wiki/Parity_(mathematics)
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* @param {number[]} integers - An array of integers.
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* @returns {number} - The parity outlier.
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* @example parityOutlier([1, 3, 5, 8, 9]) = 8
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*/
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const parityOutlier = (integers) => {
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let oddsCount = 0 // define counter for odd number(s)
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let evensCount = 0 // define counter for even number(s)
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let odd, even
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for (const e of integers) {
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2023-10-03 23:08:19 +02:00
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if (!Number.isInteger(e)) {
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// detect non-integer elements
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2023-05-01 16:16:48 +10:00
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return null
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}
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2023-10-03 23:08:19 +02:00
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if (e % 2 === 0) {
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// an even number
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2023-05-01 16:16:48 +10:00
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even = e
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evensCount++
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2023-10-03 23:08:19 +02:00
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} else {
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// an odd number
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2023-05-01 16:16:48 +10:00
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odd = e
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oddsCount++
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}
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}
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if (oddsCount === 0 || evensCount === 0) return null // array has only odd/even number(s)
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if (oddsCount > 1 && evensCount > 1) return null // array has more than one even and odd number
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return oddsCount === 1 ? odd : even
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}
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export { parityOutlier }
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