I got different questions than another poster, so sharing them here.

1. variation of https://leetcode.com/problems/add-strings/
2. some other really easy string manipulation
3. https://leetcode.com/discuss/interview-question/354854/facebook-phone-screen-cut-wood
4. another string manipulation question: given a string, you can create another string by switching the index of characters and swapping the frequencies. Check if two strings are identical. So "aab" = "bab" true