Oracle Applications Developer interview questions

Questions were based on greedy algorithms, they also asked 2 puzzles. In the second round I got a question on graphs (Flight cost with at max K destinations type) , 1 critical thinking question based on intersection of 3 circles and 1 SQL query. In 3rd round, I was asked to write program to calculate days between 2 dates given. Then I was rejected.

DSA Sheet question of removing duplicates