Amazon Interview Experience | Set 393 (On Campus For Internship)

Online Coding Round:- 
There were 2 coding questions and 20 MCQ's. 

1. Given an array find all the triplets having their sum of elements less than a given number k. 
   GeeksforGeeks Link
2. Find The N-th Magic Number.

1st Interview Round(Face To Face):-
The interviewer was very friendly. He went through my CV and asked me if I had any project. To which I replied no and told him that I am currently on a project, and later I gave him a brief explanation of it. For those who didn't do any project don't worry much. 
He asked me 2 questions 

1. Generating All the Possible Subsets(Subset Iteration). 
   GeeksforGeeks Link
2. Slight Modification of BFS on a grid. I told him my approach, and he was satisfied with that.

After I told my approach for the 2nd question he told me to write a Pseudo Code for BFS in a graph.
He was the best interviewer I faced till now. 
The interview lasted for around 45 mins.
Other people were given questions like 

1. The middle element in a linked list. 
   GeeksforGeeks Link
2. Merge Sort in a Double Linked List. 
   GeeksforGeeks Link
3. Merge Two Sorted Arrays. 
   GeeksforGeeks Link
4. Given A Binary Tree, For every Leaf Node print sum of the values from the root node to the leaf node. 
   GeeksforGeeks Link
5. Quick Sort 
   GeeksforGeeks Link
6. LCA in Binary Tree and Binary Search Tree. 
   
   • LCA in Binary Search Tree
   • LCA in binary tree

2nd Interview Round(Face To Face):- 
This interviewer was also very friendly. He also had a good knowledge of Coding. He asked me how was my previous round, I replied that it went well. And later he asked me what questions I was asked in the previous round. I told him the questions which I was asked in the previous round, and also I explained their solutions. 
He asked me 2 questions. 

1. Print the Binary Tree in A Spiral Order. 
   GeeksforGeeks Link
2. lli stands for long long int in this question.
   He gave me a question in the form of a function. And here goes the question.

// a1(size1) and a2(size2) are arrays and you
  // have to append them.
  lli* Append(lli* a1,lli* a2,lli size1,lli size2)
  {
      
  }

Simple But Wrong Solution

lli* Append(lli* a1,lli* a2,lli size1,lli size2)
  {
      lli a[size1+size2],i;
      
      for(i=0;i<size1;i++)
      {
           a[i]=a1[i];
      }

      for(i=0;i<size2;i++)
      {
           a[i+size1]=a2[i];
      }
      
      return a;
  }

I told him that the above code actually fails. He asked me why it fails. I answered him this way. The array a is actually in the function Append and once you leave the function the scope of this array ends. He asked me how to do it then. I had no idea. Later he told me that we have to allocate memory for the array using malloc. Later on, he explained to me how it works using heap memory.

For my friends, he asked the question in a different way(Merge Two Sorted Arrays).
Thanks to GeeksForGeeks For my interview preparation.