Amazon Interview Experience | On-Campus

Coding Round:

•   20 mcq questions on C, C++.
•   2 coding question  1) Given infix equation in string, return the value of expression Ex.  (2+3)*5  will return   30   2) find mean median mod of a given array

Round 1:

1. I was given an array with some numbers which denotes the denomination of coin we can use, and then i was asked to find out to make a sum using the available denomination so that number of coins used is minimum and also print the combination of coins. https://www.geeksforgeeks.org/find-minimum-number-of-coins-that-make-a-change/
2. This question was easy one . I was asked to return true if two given string having edit distance equal to or less than 1 otherwise false.
3. I was asked to return last Kth node in a linked list without using extra space and recursion. I given the solution which used two traversal of the linked list but i was asked to do this only with one traversal, then i gave him the solution with two pointers.https://www.geeksforgeeks.org/nth-node-from-the-end-of-a-linked-list/

Round 2:

1.       This question was to find the maximum distance between any two leaf node in a binary tree. https://www.geeksforgeeks.org/print-longest-leaf-leaf-path-binary-tree/
2. This question was little bit hard. The question was that there is a mad scientist who has various solution.I was given an array that contains the volume of each solution. The scientist can mix any two adjacent solution. let’s say two adjacent solution having volume a and b then the resultant solution will produce smoke volume of (a*b) and liquid of (a+b) %100. Now i was asked to find a way such that all over smoke produced is minimum.               Hint: Use same approach as chain multiplication.
3. Last question of this round was to convert a source string to target string such that at any time you can change only one alphabet of the string and resultant string (at each alteration) must be present in a dictionary which was provided at the beginning.I had to find the minimum number of alteration. I gave him a bfs approach.

Round 3:

1. I was asked to print to node of a binary tree in reverse zig zag order.
2. The second question was to tell number of islands present. 1 represents land while 0 represents water in the given matrix. adjecent 1’s comes under single islands. https://www.geeksforgeeks.org/find-number-of-islands/
3. After that they asked a nested sql query. and then asked about types of join in dbms(inner and outer).

Round 4(bar raising):

1.      I was given two strings one contains only alphabets and another contains alphabets, dot(.) and star(*). dot represents any one character and a star can represent any number of alphabets including 0 also. and I had to check whether both string match or not.
2. At last we talked about my project, he asked what i had  done during my internship, and what challenges i faced during that.
3. Then he asked some question on Operation System including demand paging and thrashing.

And, I got selected.