Knuth–Morris–Pratt algorithm #1553

Original file line number	Diff line number	Diff line change
Expand Up		@@ -9,19 +9,19 @@ describe('AutomorphicNumber', () => {
		})

		test.each([
	{ n: -3, expected: false },
	{ n: -25, expected: false },
	{ n: -3, expected: false },
	{ n: -25, expected: false }
		])('should return false when n is negetive', ({ n, expected }) => {
		expect(isAutomorphic(n)).toBe(false)
		})

		test.each([
	{ n: 7, expected: false },
	{ n: 83, expected: false },
	{ n: 0, expected: true },
	{ n: 1, expected: true },
	{ n: 376, expected: true },
	{ n: 90625, expected: true },
	{ n: 7, expected: false },
	{ n: 83, expected: false },
	{ n: 0, expected: true },
	{ n: 1, expected: true },
	{ n: 376, expected: true },
	{ n: 90625, expected: true }
		])('should return $expected when n is $n', ({ n, expected }) => {
		expect(isAutomorphic(n)).toBe(expected)
		})
Expand Down

6 changes: 3 additions & 3 deletions Project-Euler/Problem006.js

Show comments View file Open in desktop

Original file line number	Diff line number	Diff line change
		@@ -1,8 +1,8 @@
		// https://projecteuler.net/problem=6

		export const squareDifference = (num = 100) => {
	let sumOfSquares = (num)(num+1)(2*num+1)/6
	let sums = (num*(num+1))/2

	let sumOfSquares = (num * (num + 1) * (2 * num + 1)) / 6
	let sums = (num * (num + 1)) / 2

		return sums ** 2 - sumOfSquares // difference of square of the total sum and sum of squares
		}

2 changes: 1 addition & 1 deletion Search/InterpolationSearch.js

Show comments View file Open in desktop

Original file line number	Diff line number	Diff line change
Expand Up		@@ -36,4 +36,4 @@ export function interpolationSearch(arr, key) {
		}

		return -1
	}
	}

57 changes: 57 additions & 0 deletions Search/KMP.js

Show comments View file Open in desktop

Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,57 @@
	/*
	* Implements the Knuth-Morris-Pratt (KMP) algorithm for pattern searching.
	*
	* The KMP algorithm is a string searching algorithm that utilizes the concept of prefix tables or failure functions
	* to efficiently match patterns in strings. It avoids unnecessary comparisons by taking advantage of the information
	* gained from previous comparisons.
	*
	* This implementation constructs a prefix table that stores the longest proper prefix that is also a suffix for each
	* prefix of the pattern. This table is then used to guide the pattern matching process, skipping over characters that
	* are known to not match.
	*
	* The algorithm returns the starting index of the first occurrence of the pattern in the text. If the pattern is not
	* found, the algorithm returns -1.
	*
	* Reference: https://en.wikipedia.org/wiki/Knuth%E2%80%93Morris%E2%80%93Pratt_algorithm
	*/

	function KMPSearch(text, pattern) {
	let lps = new Array(pattern.length).fill(0)
	computeLPS(pattern, lps)
	let i = 0
	let j = 0
	while (i < text.length) {
	if (pattern[j] == text[i]) {
	j++
	i++
	}
	if (j == pattern.length) {
	return i - j
	} else if (i < text.length && pattern[j] != text[i]) {
	if (j != 0) j = lps[j - 1]
	else i = i + 1
	}
	}
	return -1
	}

	function computeLPS(pattern, lps) {
	let len = 0
	let i = 1
	while (i < pattern.length) {
	if (pattern[i] == pattern[len]) {
	len++
	lps[i] = len
	i++
	} else {
	if (len != 0) {
	len = lps[len - 1]
	} else {
	lps[i] = 0
	i++
	}
	}
	}
	}

	export { KMPSearch }

27 changes: 27 additions & 0 deletions Search/test/KMP.test.js

Show comments View file Open in desktop

Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,27 @@
	import { KMPSearch } from '../KMP'

	describe('Rabin-Karp Search', function () {
	test('KMP algorithm test 1', () => {
	let text = 'AAAAA'
	let pattern = 'AAA'
	expect(KMPSearch(text, pattern)).toBe(0)
	})

	test('KMP algorithm test 2', () => {
	let text = 'ABABDABACDABABCABAB'
	let pattern = 'DABA'
	expect(KMPSearch(text, pattern)).toBe(4)
	})

	test('KMP algorithm test 3', () => {
	let text = 'ABABDABACDABABCABAB'
	let pattern = 'ABABCABAB'
	expect(KMPSearch(text, pattern)).toBe(10)
	})

	test('KMP algorithm test 4', () => {
	let text = 'ABABDABACDABABCABAB'
	let pattern = 'XYZ'
	expect(KMPSearch(text, pattern)).toBe(-1)
	})
	})

Navigation Menu