# Coding Interview Questions

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Sort: Popular Date

### Software Development Engineer at Amazon.com

Feb 27, 2010
 “Implement a function to validate whether a given binary tree is a BST (i.e. write an isBST() function).”

Jun 11, 2010
 “Write a function that divides two numbers without using the divide '/' operator.”

### Software Engineer, Infrastructure at Facebook

Aug 5, 2012
 “Write a function that takes 2 arguments: a binary tree and an integer n, it should return the n-th element in the inorder traversal of the binary tree.”

### Software Engineer In Test at Google

Jan 15, 2010
 “You are a parking lot attendant in a lot that has one open spot, and you want to move the cars from their original positions into a new arrangement. Create a program that will print out instructions...”

### Software Engineer at Amazon.com

May 12, 2010
 “Given a list of integers, some of which may be negative, extract the pair that sums to the largest number.”

### Test Engineer at Qualcomm

Nov 19, 2010
 “Initialize a 5 by 5 array with this sequence. 1 2 3 4 5 6 4 8 9 10 11 12 9 14 15 16 17 18 16 20 21 22 23 24 25”

### Machine Learning Software Engineer at Facebook

Jan 21, 2010
 “Suppose you have a matrix of numbers. How can you easily compute the sum of any rectangle (i.e. a range [row_start, row_end, col_start, col_end]) of those numbers? How would you code this?”

### Senior Software Engineer at Google

May 5, 2009
 “Look for a string in a very long string - a needle in a haystack. Write the program in pseudo-code.”