Wrap Matching Substrings in Bold Tags

During a machine learning engineer phone screen, the coding task was:

You are given a string text and a list of strings patterns. Return a new string where every substring of text that matches any string in patterns is wrapped in HTML-style bold tags: <b> and </b>.

Rules:

• If two matched ranges overlap, they must be merged into one bold segment.
• If two matched ranges are adjacent, they should also be merged into one bold segment.
• The output should contain the minimum number of bold tag pairs needed to cover all matches.

Example 1:

• Input: text = "abcxyz123", patterns = ["abc", "123"]
• Output: "<b>abc</b>xyz<b>123</b>"

Example 2:

• Input: text = "aaabbcc", patterns = ["aaa", "aab", "bc"]
• Output: "<b>aaabbc</b>c"

Implement a function that returns the formatted string.

Wrap Matching Substrings in Bold Tags

Constraints

• 0 <= len(text) <= 1000
• 0 <= len(patterns) <= 100
• 1 <= len(patterns[i]) <= 100 for each pattern that exists
• Both text and patterns[i] consist of lowercase English letters

Hints

1. Try marking which character positions belong to at least one matched pattern, then build the answer from those marks.
2. While scanning from left to right, keep track of the furthest end index of any pattern that starts at or before the current position.