```# System Design question area # long url https://www.addgene.org/pooled-library/morris-lab-celltag/ # short url https://www.addgene.org/ab1s3eef2 # base domain name that should stay consistent https://www.addgene.org/ ``` ```java // time O(N) // sapce O(N) list1 = [1,2,3] list2 = [1,1,1] public static List<Integer> getCommon(int[] list1, int[] list2) { int n1 = list1.length; int n2 = list2.length; Set<Integer> set = new HashSet<>(); // O(N) for (int i = 0; i < n1; i++) { set.add(list1[i]); } Set<Integer> set2 = new HashSet<>(); // O(N) for (int i = 0; i < n2; i++) { // O(1) if (set.contains(list2[i])) { set2.add(list2[i]); } } List<Integer> result = new ArrayList<>(); for (Integer element : set2) { result.add(element); } return result; } ``` ``` Database Design Question table name : Order OrderID: String, Primary key Name varchar(20) Shipping_Street varchar(20) Shipping_City varchar(20) Shipping_state varchar(2) CA, MA, ME, ABC Shipping_zip_code varchar(5) 04103 add requirement : search the shipping address which is in Maine select * from XX table where Shipping_state = "ME" ```