Amazon Placement Paper - 1

First round: Technical and aptitude test.

It comprised of 20 technical objective Questions and two programs to be solved in 1 hr 30 mins.

1. Question on fork () system call.

Code was given with few forks and asked to find out number of child processes and how many times a given printf statement will be executed.

2. C language Question dangling pointers.

3. A numerical on 2-level page table in os.

4. Question like which of the following is used by java.

A) nfa
b) dfa
c) pda
d) turing machine

5. Question on threads.

Which portion is shared between process and threads (code section, processor register etc).

6. Question on tree.

Preorder traversal of a bst was given we have to find out its postorder traversal.

7. C language Question on format specifier.

Like which of the following is not a format specifier.

8. Java Question on string concatenation operator (+) inside system.out.println();

9. Mix of printf and fork was given and we were asked the output.

10. Page reference string were given and we have to find out number of page faults in
fifo, lru and optimal page replacement policy.

11. Question on thrashing from os.

2 programs.

1st) An array containing mix of +ve and -ve numbers were given and we have to arrange those numbers so that final array has alternating +ve and -ve numbers but without changing the original order.

2nd) program based on keypad of a mobile.Keypad has keys with each key having few digits and alphabets on it.A number was given say 235 then we have to write a program that finds all permutations of alphabets while typing 235 like adj, adk, adl and so on. Without changing the original sequence.