Kata

If we alternate the vowels and consonants in the string "have", we get the following list, arranged alphabetically: ['ahev', 'aveh', 'ehav', 'evah', 'have', 'heva', 'vahe', 'veha']. These are the only possibilities in which vowels and consonants are alternated. The first element, ahev, is alphabetically lowest.

Given a string:

• alternate the vowels and consonants and return the lexicographically lowest element in the list
• If any two or more vowels or consonants must follow each other, return "failed"
• if the number of vowels and consonants are equal, the first letter of the result must be a vowel.

Examples:

solve("codewars") = "failed". However you alternate vowels and consonants, two consonants must follow each other
solve("oruder") = "edorur"
solve("orudere") = "ederoru". This is the only option that allows you to alternate vowels & consonants.

In C, return an allocated string even if the response is "failed".

Vowels will be any of "aeiou". Input will be a lowercase string, no spaces. See test cases for more examples.

Good luck!

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