This depends entirely on if it was liquid or dry yeast.
Active dry yeast is very hardy. Most dry yeast strains can be kept at room temperature for 3+ months with negligable impact on the final product. Anecdotally I've gone even longer and still had a strong fermentation.
STORAGE During transport : The product can be transported and stored
at room temperature for periods of time not exceeding 3 months
without affecting its performance.
To answer the original question for others who may find this link:
Yeast stored at 30℃ for 3 weeks would be perfect still.
Though you said you put it into the freezer, this is where you might have done some real damage. As Evil Zymurgist said, if it's dry yeast you might be okay, just make a starter, and if they are still viable just let the yeast recover it's strength before you use it.
If it was a liquid yeast, and it froze solid, they are all probably dead.
If the liquid yeast was still 100% a liquid when pulled it out of the freezer, then just make a starter; They are probably fine.