Algorithms and Data Structures implemented in JavaScript for beginners, following best practices.
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/**
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* @function isPalindromeIterative
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* @description isPalindromeIterative function checks whether the provided input is palindrome or not
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* @param {String | Number} x - The input to check
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* @return {boolean} - Input is palindrome or not
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* @see [Palindrome](https://en.wikipedia.org/wiki/Palindrome)
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*/
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/*
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* Big-O Analysis
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* Time Complexity
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- O(N) on average and worst case scenario as input is traversed in linear fashion
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- O(N) on best case scenario, even when input has length of 1, because toString() method takes O(N)
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* Space Complexity
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- O(1)
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*/
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export function isPalindromeIterative (x) {
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if (typeof x !== 'string' && typeof x !== 'number') {
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throw new TypeError('Input must be a string or a number')
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}
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// Convert x to string whether it's number or string
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const string = x.toString()
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const length = string.length
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if (length === 1) return true
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// Apply two pointers technique to compare first and last elements on each iteration
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for (let start = 0, end = length - 1; start < end; start++, end--) {
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// Early return if compared items are different, input is not a palindrome
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if (string[start] !== string[end]) return false
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}
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// If early return in condition inside for loop is not reached, then input is palindrome
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return true
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}
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