LeetCode 809 Expressive Words gives you a string s and an array of query words. A word is stretchy if you can make it equal to s by extending groups of identical characters. A group can only be extended if the resulting group in s has or more characters. This problem appears in Google interviews because it tests careful two-pointer logic with string matching rules.
For example, if s = "heeellooo" and words = ["hello"], the answer is . You can extend "ee" to "eee" (group of ) and "o" to "ooo" (group of ), but each extended group must reach at least .
Think about this: how do you compare two strings group by group? What condition decides whether a group can stretch?