A CME Globex monitoring tool must determine whether an operational note can be assembled from letters appearing in a collection of magazine titles. Each title may be selected at most once, and all normalized letters from a selected title are available. Return the smallest number of titles needed and their zero-based indices.
Normalize both titles and the note by keeping only English letters a-z and converting uppercase letters to lowercase. Letter order does not matter. If multiple minimum-size selections exist, return the lexicographically smallest list of indices. If the note cannot be formed, return [-1, []].
Implement min_titles_for_note(titles, note), where titles is a list of strings and note is a string. Return a two-element list [count, indices], where count is the minimum number of selected titles and indices is the corresponding sorted index list. For an empty normalized note, return [0, []].
def min_titles_for_note(titles, note):