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6aa3314b93
* fix: fixed error in the MaxProductOfThree algorithm Fixed the error in the MaxProductOfThree by initializing the max and min variables to null instead of -1. The checks were then altered to check for null instead of -1. Also wrote more tests, which randomly generated small arrays and compared the output of the maxProductOfThree-algorithm to the output of a slower, but complete, function which calculates all posible triple-products of the values of the array. Fixes: #1294 * fix: Added newlines at the end of the files
39 lines
1.1 KiB
JavaScript
39 lines
1.1 KiB
JavaScript
/**
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* Given an array of numbers, return the maximum product
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* of 3 numbers from the array
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* https://wsvincent.com/javascript-three-sum-highest-product-of-three-numbers/
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* @param {number[]} arrayItems
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* @returns number
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*/
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export function maxProductOfThree (arrayItems) {
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// if size is less than 3, no triplet exists
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const n = arrayItems.length
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if (n < 3) throw new Error('Triplet cannot exist with the given array')
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let max1 = arrayItems[0]
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let max2 = null
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let max3 = null
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let min1 = arrayItems[0]
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let min2 = null
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for (let i = 1; i < n; i++) {
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if (arrayItems[i] > max1) {
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max3 = max2
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max2 = max1
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max1 = arrayItems[i]
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} else if (max2 === null || arrayItems[i] > max2) {
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max3 = max2
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max2 = arrayItems[i]
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} else if (max3 === null || arrayItems[i] > max3) {
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max3 = arrayItems[i]
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}
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if (arrayItems[i] < min1) {
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min2 = min1
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min1 = arrayItems[i]
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} else if (min2 === null || arrayItems[i] < min2) {
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min2 = arrayItems[i]
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}
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}
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const prod1 = max1 * max2 * max3
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const prod2 = max1 * min1 * min2
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return Math.max(prod1, prod2)
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}
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