most common facebook coding interview questions
the 15 most asked questions in a facebook coding interview
Arrays
Move zeros to the left
Problem statement
Given an integer array, move all elements that are equal to 0 to the left while maintaining the order of other elements in the array.
Merge overlapping intervals
Problem statement
Given a list of intervals, merge all the overlapping intervals to produce a list that has only mutually exclusive intervals.
linked lists
Add two integers
Problem statement
Given the head pointers of two linked lists where each linked list represents an integer number (each node is a digit), add them and return the resulting linked list.
Merge two sorted linked lists
Problem statement
Given two sorted linked lists, merge them so that the resulting linked list is also sorted.
trees
Convert binary tree to doubly linked list
Problem statement
Convert a binary tree to a doubly linked list so that the order of the doubly linked list is the same as an in-order traversal of the binary tree. After conversion, the left pointer of the node should be pointing to the previous node in the doubly linked list, and the right pointer should be pointing to the next node in the doubly linked list.
Level order traversal of binary tree
Problem statement
Given a binary tree and a number ‘S’, find all paths from root-to-leaf such that the sum of all the node values of each path equals ‘S’.
strings
Reverse words in a sentence
Problem statement
Reverse the order of words in a given sentence (an array of characters).
String segmentation
Problem statement
Given a dictionary of words and an input string tell whether the input string can be completely segmented into dictionary words.
dynamic programming
Find maximum single sell profit
Problem statement
Given a list of daily stock prices (integers for simplicity), return the buy and sell prices for making the maximum profit. We need to maximize the single buy/sell profit. If we can't make any profit, we'll try to minimize the loss.
Math and stats
Calculate the power of a number
Problem statement
Given a double, 'x', and an integer, 'n', write a function to calculate 'x' raised to the power 'n'.
backtracking
Find all possible subsets
Problem statement
You are given a set of integers and you have to find all the possible subsets of this set of integers.
Graphs
Clone a directed graph
Problem statement
design
Serialize / deserialize binary tree
Problem statement
Serialize a binary tree to a file and then deserialize it back to a tree so that the original and the deserialized trees are identical.
sorting and searching
Find the high and low index
Problem statement
Given a sorted array of integers, return the low and high index of the given key. Return -1 if not found. The array length can be in the millions with many duplicates.
Search rotated array
Problem statement
Search for a given number in a sorted array that has been rotated by some arbitrary number.
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