# Amazon Interview | Set 70 (On-Campus For Internship)

Online Round Coding Question:
1. Given a float number 7.64, convert it into the string WITHOUT using any inbuilt function/library.
```for eg:
input
float no.: 7.64
output
string: 7.64```
2. Given the inorder and preorder traversals of a Binary Tree, output the postorder traversal of it.
```for eg:
input:
Inorder: 7, 8, 4, 1, 6, 2, 5
Preorder: 1, 4, 7, 8, 2, 6, 4
output:
Postorder: 8, 7, 4, 6, 5, 2, 1```
Round 1 written:
1. Given a string find the length of longest substring which has none of its character repeated?
```for eg:
i/p string:
abcabcbb
length of longest substring with no repeating charcters: 3 (abc)```
2. Given a link list with right pointers and each element of the list has a down link contains another link list with down pointers as:
``` 5 -> 7 -> 9 -> 18
|    |    |    |
10    6    14   20
|    |    |    |
11    8    19   22
|    |         |
12    13        24
|
15```
each right and down list are sorted. Write a function flatten() which flattens this link list to a single link list with all the elements in sorted order as: 5->6->7->8->9->10->11->12->13->14->15->18->19->20->22->24
PI Round 1: The interview started with discussions and questioning about the internship project and other projects mentioned in my Resume. After the discussions about projects interviewer asked a question on string the question was:
1. A string of length n and an integer m was given, give an algo. to rotate the string counter clockwise by m. I was asked to give all the check conditions for input m. Then the interviewer asked me to write a code for the same with a strict guideline that there should not be any mistake in the code ;).
2. After this he asked me about heap, min and max heap, insertion and deletion in a heap. He asked me to prove that the time complexity of inserting n elements in a heap. At-least he asked about the uses of heap data structure and other data structure which are implemented using heap.
PI Round 2:
1. What is the difference b/w abstract and interface class?
2. Write a program to create single thread and print “Hello World”, stating all the arguments of createThread function?
3. What is a deadlock and what are the condition necessary for the deadlock to occur?
4. What is a cache memory and how it is implemented?
5. Explain LRU, FIFO and other page replacement algorithms?
6. write a code to implement LRU cache and then implement full cache memory?

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