Co-Occurrence Counter in Strings | Dataford Interview Questions

Tessian Guardian analyzes email text for combinations of terms that may indicate a risky message. Given an email body and two distinct target words, return the number of pairs formed by one occurrence of each target word anywhere in the text.

Matching is case-insensitive. A word is a contiguous sequence of ASCII letters, and punctuation separates words. Each occurrence is counted independently, so if word1 appears twice and word2 appears three times, the result is six.

Formal Specification

Implement count_cooccurrences(text, word1, word2).

Input: text, word1, and word2, all strings. The target words contain only ASCII letters and are distinct.
Output: An integer representing the number of unordered occurrence pairs containing one occurrence of each target word.

Constraints

1 <= len(text) <= 10^6
1 <= len(word1), len(word2) <= 50
word1 and word2 are distinct ASCII-letter strings
Matching is case-insensitive
Punctuation separates words
The result fits in a signed 64-bit integer

Function Signature

def count_cooccurrences(text, word1, word2):

Your question is Co-Occurrence Counter in Strings. Start with the requirements in the Question tab.

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Problem