Technical Interview 3

This was more of a general discussion on various fields of computer science rather than problem solving round.

Problem 1

You have a two files a.txt and b.txt having two numbers with upto billion digits. You have to calculate the sum of two numbers.

Solution

My solution was to first move the file pointer of the both files at the end and then start adding the digits and carry and consequently moving backwards and store the result into a new file. Finally create another file and save the reversed contents of previous result file. He was satisfied but then restricted the backward traversal. I told that we can use recursion to return the carry. He asked if any data structure can be used for this problem. I replied with linked list, because large amount of continuous memory cannot be allocated but linked list does not use continuous memory.

Problem 2

You are given a grid of alphabets. You have to print the coordinates of all the starting points from where word ‘AMAZON’ can be formed. You can move up, down, left and right.

Solution

I gave a solution using DFS and DP. It was difficult to explain but I tried my best. I guess he was expecting a more simpler solution but he was satisfied. He told me to write the code my idea.

Amazon pool campus placement drive was conducted in March 2019. There were total five rounds, first round being an online coding round was held on Hackerearth followed by three technical interviews and one bar raiser cum technical round.