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alexander
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‎Bit-Manipulation/BitwiseLogTwo.js‎

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/**
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* https://handwiki.org/wiki/Binary_logarithm
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* Approximate log2 using only bitwise operators
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* @param {number} n
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* @returns {number} Log2 approximation equal to floor(log2(n))
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*/
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export const bitwiseLogTwo = (n) => {
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let result = 0
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while (n >> 1) {
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n >>= 1
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result++
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}
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return result
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}

‎Bit-Manipulation/LogTwo.js‎

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‎Bit-Manipulation/test/BitwiseLogTwo.test.js‎

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import { bitwiseLogTwo } from '../BitwiseLogTwo'
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for (let i = 1; i < 100; i++) {
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test('log2(' + i + ')', () => {
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expect(bitwiseLogTwo(i)).toBe(Math.floor(Math.log2(i)))
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})
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}

‎Bit-Manipulation/test/LogTwo.test.js‎

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