Break both s and each query word into groups of consecutive identical characters. For "heeellooo", you get groups: (h,1), (e,3), (l,2), (o,3).
Then compare group by group. For a word to be stretchy, conditions must hold for every group:
The characters must match.
Either the counts are equal, or the count in s is at least (meaning the group was stretched).
If any group fails either condition, that word is not stretchy. Count how many words pass all groups.