2020-10-04 14:22:28 -03:00
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/**
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2023-10-03 23:08:19 +02:00
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* What is a palindrome? https://en.wikipedia.org/wiki/Palindrome
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* Receives a string and returns whether it can be rearranged to become a palindrome or not
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* The string can only be a palindrome if the count of ALL characters is even or if the ONLY ONE character count is odd
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* Input is a string
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*
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**/
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2020-10-04 14:22:28 -03:00
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2021-10-11 14:07:10 +02:00
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export const palindromeRearranging = (str) => {
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2020-10-04 14:22:28 -03:00
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// check that input is a string
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if (typeof str !== 'string') {
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return 'Not a string'
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}
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// Check if is a empty string
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2023-08-21 15:06:43 -03:00
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if (!str) {
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2020-10-04 14:22:28 -03:00
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return 'Empty string'
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}
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// First obtain the character count for each character in the string and store it in an object.
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// Filter the object's values to only the odd character counts.
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const charCounts = [...str].reduce((counts, char) => {
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counts[char] = counts[char] ? counts[char] + 1 : 1
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return counts
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}, {})
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// If the length of the resulting array is 0 or 1, the string can be a palindrome.
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2023-10-03 23:08:19 +02:00
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return (
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Object.values(charCounts).filter((count) => count % 2 !== 0).length <= 1
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)
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2020-10-04 14:22:28 -03:00
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}
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// testing
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2021-10-11 14:07:10 +02:00
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// > palindromeRearranging('aaeccrr')
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// true
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// > palindromeRearranging('leve')
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// false
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