# Amazon.com Phone Interviews

Round #1: Given two arrays of integers, get the union of them.

Round #2: Testing, OOD and Regex questions.  Design classes for a mathematical equation. Find all phone numbers in a big file.

Round #3: Given an array of integers and a target number, find all two numbers in the array that sum up to the target number with time complexity of order O(n)

Round #4 out of ???

Practice questions

1. Given an array of integers find any two of the numbers in the array sum up to another given number in the array.

2. There are two linked lists. You need to find if there is a intersection in these lists. By intersection what he meant was that if two link lists merged at some point.

3. After solving the above he asked me the node at which they will merge.

4. Given a graph , you are given a particular node and asked all the node which can be accessed from this node and all node which can access this node. (Directed graph)

5. If 2nd October 2001 was a palindrome : 10022001 which date before this was palindrome?

6. Implement “toString” in Collection framework

7. Thread pooling program :- checked on Design patterns, Threads fundamentals, Resource sharing and synchronization

8. Post Order traversal

9. Why is hash code there is JAVA object class

10. How is hash tables implemented in Java.

11. Two puzzles

a) There is one machine which gives Pepsi, another coke and third which gives both.

These machines are wrongly marked in such a way that none of them have correct

label (viz coke,pepsi,code/pepsi). Now how will you re-label them properly if you

are allowed to switch on just single machine. By switching on the machine you can

come to know what that machine provides.

b) You are given a rectangular piece of paper. Now you cut one rectangular piece of any

size and orientation in this paper. How will you cut a single line on resultant paper so

that each of the cut pieces have same area and are congruent.