481. Alternating Case Word Joiner

Given an array of strings words, join them into a single string where each word is separated by a hyphen -. However, you must transform the words based on their index: words at even indices (0, 2, 4...) should be converted to all uppercase, and words at odd indices (1, 3, 5...) should be converted to all lowercase.

Example:
Input: words = ["Hello", "World", "Code"]
Output: "HELLO-world-CODE"

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