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Commit 8bf29fe

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merge: Optimize the space complexity of the fibonacci algo (#899)
* docs: update js doc * feat: add number type validation condition * pref: Optimize space complexity remove the Array from the algo and used two flag varible to calculate last two numbers & optimize the sapce complexity O(n) to O(1) * test: add test case for invalid types
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‎Dynamic-Programming/FibonacciNumber.js

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@@ -1,19 +1,27 @@
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/**
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* @function Fibonacci
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* @function fibonacci
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* @description Fibonacci is the sum of previous two fibonacci numbers.
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* @param {Integer} N - The input integer
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* @return {Integer} fibonacci of N.
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* @see [Fibonacci_Numbers](https://en.wikipedia.org/wiki/Fibonacci_number)
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*/
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const fibonacci = (N) => {
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// creating array to store values
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const memo = new Array(N + 1)
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memo[0] = 0
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memo[1] = 1
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for (let i = 2; i <= N; i++) {
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memo[i] = memo[i - 1] + memo[i - 2]
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if (!Number.isInteger(N)) {
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throw new TypeError('Input should be integer')
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}
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return memo[N]
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// memoize the last two numbers
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let firstNumber = 0
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let secondNumber = 1
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for (let i = 1; i < N; i++) {
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const sumOfNumbers = firstNumber + secondNumber
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// update last two numbers
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firstNumber = secondNumber
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secondNumber = sumOfNumbers
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}
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return N ? secondNumber : firstNumber
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}
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export { fibonacci }

‎Dynamic-Programming/tests/FibonacciNumber.test.js

Lines changed: 7 additions & 1 deletion
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import { fibonacci } from '../FibonacciNumber'
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describe('FibonacciNumber', () => {
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describe('Testing FibonacciNumber', () => {
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it('Testing for invalid type', () => {
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expect(() => fibonacci('0')).toThrowError()
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expect(() => fibonacci('12')).toThrowError()
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expect(() => fibonacci(true)).toThrowError()
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})
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it('fibonacci of 0', () => {
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expect(fibonacci(0)).toBe(0)
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})

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