Count anagram-based replacements per phrase

Problem

You are given:

• phrases: a list of strings, where each string is a phrase containing words separated by single spaces.
• words: a list of strings.

A word a can be replaced by a word b if a and b are anagrams (they contain the same letters with the same frequencies; order does not matter).

For each phrase, compute how many different phrases can be formed by replacing each replaceable word in the phrase with any anagram from words.

• Words in the phrase that have no anagram in words must stay unchanged.
• If no word in the phrase has any anagram in words (i.e., no replacement is possible), return 0 for that phrase.

Return a list of integers, one per phrase.

Example

Input:

• phrases = ["hello world", "below elbow"]
• words = ["below", "elbow"]

Explanation:

• Phrase 1: neither hello nor world has an anagram in words → no replacement possible → 0
• Phrase 2: below and elbow are anagrams, and both appear in words. Each of the two positions can be replaced by either below or elbow → 2 * 2 = 4

Output:

• [0, 4]

Requirements / Notes

• Treat anagrams case-sensitively or case-insensitively consistently (state your choice in implementation; a common assumption is lowercase inputs).
• You may assume phrases contain only alphabetic words and spaces.
• The result may exceed 32-bit integer range; use 64-bit if needed.