# Amazon-Job-Interview-Question-2012

Written Test has 2 Sections A, B In Section A there were 20 Questions:
Time :30 min
Multiple choice
Aptitude< 1.Two tables emp (empid,name,deptid,sal) and dept(deptid,deptname) are there.write a query which displays empname,corresponding deptname also display those employee names who donot belong to any dept. 2.Display the employees whose salary is less than average salary. 3.what is the output of the program main() { int c=5; printf("%d\n%d\n%d",c,c<<2,c>> 2); } 4. main() { int a[8][10],c=0,i,j; for(i=0;i<10; i++) for(j=0; j<8;j++) a[j][i]=c++; printf("%d",a[3][6]); } 5.What is the wrong in this program main() { char *p,*q; p=(char *)malloc(25); q=(char*) malloc(25); strcpy(p,"amazon" ); strcpy(q,"hyd"); strcat(p,q); printf("%s",p); } 6.write prefix and post fix notation for (a+b)*c-(d+e)^(f-g) 7.what is the output of the program main() { int i=5; printf("%d",fun(fun(fun(fun( fun(i)))))); } void fun (int i) { if(i%2) return (i+(7*4)-(5/2)+(2*2)); else return (i+(17/5)-(34/15)+(5/2)); } 8.When it is always true boolean fun (node *p) { return ((p==null)||(p->next==null)|| (p->info<=p->next->info)&&( fun(p->next))); } a) when list is empty or has one node b) when the ele are sorted in non decreasing order c) when the ele are sorted in non increasing order 9.what is x here (x&&!(x&(x-1))==1) a) x is always a prime b) x is a power of 2 c) x is even d)x is odd 10 .What is the difference between deep copy and shallow copy 11.In java what is the difference between sleep() and wait() . 12.What happens when the parent process of a child process exits before the child ? 13.There are three persons A,B,C .A shots the target 6 times out of 7 shots .B shots 4 out of 5 shots .Then what is the probability of hitting the target twice when 2 persons are selected at random. 14.what is valid in cpp char *cp; const char *cpp; 1) cpp=cp; 2) cp=cpp; 15.write program to swap 2 variables without using extra memory. 16.write a shell command to find all java files present in nested directories. 17.There are 6 pairs of black socks and 6 pairs of white socks.What is the probability to pick a pair of black or white socks when 2 socks are selected randomly in darkness. 18.A string of alphanumeric is there.Find a string that starts with b and ends with 3 characters. section B (we have to write programs) time:30 min     1. There is a sorted array which is of very large size.In that all except one no. are repeated once.How to find that non repeated no.     2. There are 2 linked lists.Those 2 lists are meeting at a point.How to find that meeting point.                         Interview Questions :
1. Given a Binary Search Tree, write a program to print the kth smallest element without using any static/global variable. You can?t pass the value k to any function also.

2. What are the 4 basics of OOP?

3. Define Data Abstraction. What is its importance?

4. Given an array of size n. It contains numbers in the range 1 to n. Each number is present at least once except for 2 numbers. Find the missing numbers.

5. Given an array of size n. It contains numbers in the range 1 to n. Find the numbers which aren?t present.

6. Given a string,find the first un-repeated character in it? Give some test cases

7. You are given a dictionary of all valid words. You have the following 3 operations permitted on a word: delete a character, insert a character, replace a character. Now given two words - word1 and word2 - find the minimum number of steps required to convert word1 to word2. (one operation counts as 1 step.)

8. Given a cube of size n*n*n (i.e made up of n^3 smaller cubes), find the number of smaller cubes on the surface. Extend this to k-dimension.

9. What is a C array and illustrate the how is it different from a list.

10. What is the time and space complexities of merge sort and when is it preferred over quick sort?

11. Write a function which takes as parameters one regular expression(only ? and * are the special characters) and a string and returns whether the string matched the regular expression.

12. Given n red balls and m blue balls and some containers, how would you distribute those balls among the containers such that the probability of picking a red ball is maximized, assuming that the user randomly chooses a container and then randomly picks a ball from that.

13. Find the second largest element in an array with minimum no of comparisons and give the minimum no of comparisons needed on an array of size N to do the same.

14. Given an array of size n, containing every element from 1 to n+1, except one. Find the missing element.

15. How do you convert a decimal number to its hexa-decimal equivalent.Give a C code to do the same

16. Explain polymorphism. Provide an example.

17. Given an array all of whose elements are positive numbers, find the maximum sum of a subsequence with the constraint that no 2 numbers in the sequence should be adjacent in the array. So 3 2 7 10 should return 13 (sum of 3 and 10) or 3 2 5 10 7 should return 15 (sum of 3, 5 and 7)

18. You are given some denominations of coins in an array (int denom[])and infinite supply of all of them. Given an amount (int amount), find the minimum number of coins required to get the exact amount. What is the method called?

19. Given an array of size n. It contains numbers in the range 1 to n. Each number is present at least once except for 1 number. Find the missing number

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Written test.
They concentrate on every field of computer science. They asked c, data structure, TOC(context free and context sensitive grammar, regular languages. DBMS unix was not there.
There were two subjective questions.
1. The first one was "given two lists write a function which returns a list which is the intersection of the two lists.the original lists should remain same.
(Intersection - if first list is say,1,20 3,45 and second list is 3,24 ,45,90,68 then intersection should be 3,45 )

2. The second was given two nodes of a binary tree find the closest ancestor of the two nodes.
Note:consider binary tree and binary search tree also.

In short answer type questions, the questions were -
1.There was an aptitude's question in which P(A) and P(B) were given and we had to find P(B/A) and P(A/B) when A and B are independent events.

2.What is the probability that the the 4 digit's no. which is formed by using the digits 1,2,3,4,5,6 is divisible by 4.

3.What tree traversal gives the no. in sorted order.Inorder,preorder or postorder ?

4.Preorder and inorder traversal was given and we had to find the tree.

5. Which sorting algorithm takes best and worst time complexity as O(nlogn)?

6.A dbms query was asked to find the second largest no. of book sold.(i don't remember the question exactly)