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e112434dee
* Add prettier config * test: add test to check for absolute function * chore: es5 to es6 * test: add test to check mean function * test: add test for sum of digit * test: add test for factorial * test: add test for fibonnaci * test: add test for find HCF * test: add test for lcm * test: add gridget test * test: add test for mean square error * test: add test for modular binary exponentiation * test: add tests for palindrome * test: add test for pascals triangle * test: add tests for polynomial * test: add tests for prime check * test: add tests for reverse polish notation * test: add tests for sieve of eratosthenes * test: add tests for pi estimation monte carlo method * chore: move tests to test folder * chore: fix standardjs errors
49 lines
1.1 KiB
JavaScript
49 lines
1.1 KiB
JavaScript
/**
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* A palindrome is any string that can be reversed and still be the same.
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* An example of one is 'radar', since it is spelled the same even after
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* being reversed. One method to check if a
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*
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* Here's how this works recursively:
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*
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* Palindrome('radar')
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* true && Palindrome('ada')
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* true && true && Palindrome('d')
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* true && true && true && true
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*
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* @flow
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* @complexity: O(n)
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*/
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const PalindromeRecursive = (string) => {
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// Base case
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if (string.length < 2) return true
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// Check outermost keys
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if (string[0] !== string[string.length - 1]) {
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return false
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}
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return PalindromeRecursive(string.slice(1, string.length - 1))
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}
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const PalindromeIterative = (string) => {
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const _string = string
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.toLowerCase()
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.replace(/ /g, '')
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.replace(/,/g, '')
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.replace(/'.'/g, '')
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.replace(/:/g, '')
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.split('')
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// A word of only 1 character is already a palindrome, so we skip to check it
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while (_string.length > 1) {
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if (_string.shift() !== _string.pop()) {
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return false
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}
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}
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return true
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}
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export { PalindromeIterative, PalindromeRecursive }
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