Arrays
Determine if the sum of three integers is equal to the given value
Problem Statement
Given an array of integers and a value, determine if there are any three integers in the array whose sum equals the given value.
Set columns and rows as zeros
Problem Statement
Given a two-dimensional array, if any element within is zero, make its whole row and column zero.
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.
Intersection point of two linked lists
Problem Statement
Given the head nodes of two linked lists that may or may not intersect, find out if they do in fact intersect and return the point of intersection. Return null otherwise.
Trees
Convert binary tree to doubly linked list
Problem Statement
Given a binary tree, populate an array to represent its zigzag level order traversal. You should populate the values of all nodes of the first level from left to right, then right to left for the next level and keep alternating in the same manner for the following levels.
Is binary search tree?
Problem Statement
Given a binary tree, figure out whether it's a BST.
Strings
Reverse words in a sentence
Problem Statement
Given a sentence (an array of characters), reverse the order of words.
Segment string into dictionary words
Problem Statement
We are given a dictionary of words and a large input string. We have to find out whether the input string can be completely segmented into the words of a given dictionary.
Dynamic Programming
How many ways can you make change with coins and a total amount
Problem Statement
Given coins denominations and total amount, find out the number of ways to make the change.
Math and Stats
Given a set of integers, find all subsets
Problem Statement
We are given a set of integers and we have to find all the possible subsets of this set of integers.
Backtracking
Print balanced parentheses for a given number 'n'
Problem Statement
Print all braces combinations for a given value n so that they are balanced.
Graphs
Minimum Spanning tree
Problem Statement
Find the minimum spanning tree of a connected, undirected graph with weighted edges.
Design
Serialize / deserialize a 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
Search for a given number in rotated array
Problem Statement
Search for a given number in a sorted array that has been rotated by some arbitrary number. Return -1 if the number does not exist. Assume that the array does not contain duplicates.
Closest meeting point
Problem Statement
Given N people on an MxM grid, find the point that requires the least total distance covered by all people to meet at that point.
