MetLife Interview Questions

MetLife is a start-up in medical e-commerce industry. Interview process is 1 online coding test followed by 2 f2f interviews.

Could not recollect the online coding test problems.
Below are the interview questions

Round-1
1) Find all anagrams in a given sorted dictionary
2) Given pack of cards represented as A1,A2…A13 and B1,B2,..B13, and C1,c2,…c13 and d1,d2..d13.
You are given a file which has 51 card numbers. Only 1 card is missing. Find the missing card.
3) How do you write an order service which scales horizontally. Into how many services can you split this. An architecture/design diagram and explanation is required

Round-2
1) http://www.programmerinterview.com/index.php/puzzles/25-horses-3-fastest-5-races-puzzle/
2) http://www.mathsisfun.com/puzzles/weighing-9-balls-solution.html
3) Write JSON Parser. What are the Data Structures used for this?
4) Write DFS code. What are the Data Structures used for this?
5) https://www.geeksforgeeks.org/largest-sum-contiguous-subarray/
6) In an array all elements are repeated twice except one element. Find the element.
eg: 2, 3, 4, 4, 3 — In this 2 is the element which is not repeated.