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