40 Algorithm Challenge Booklet Answers -

Reading a file of customer orders and awarding cards to those with >20 orders.

Use a hash map for O(n) time instead of O(n²) brute force. 40 Algorithm Challenge Booklet Answers

1->2->3->4->NULL → 4->3->2->1->NULL . Answer (Python - Iterative): Reading a file of customer orders and awarding