Review-Problems

Just solving a list of interview questions for algorithms and data structures review.

Arrays/Strings:

• Determine if a string is a palindrome
• Merge two sorted arrays
• Reverse an array in place
• Determine if string is a substring
• Sorting algorithms: quicksort, mergesort, bucketsort, and countingsort
• Binary search in a sorted rotated array
• Matrix multiplication
• Find all duplicates in an array

Linked List:

• Reverse a singly linked list
• Delete/Insert a node in a linked list
• Detect if there is a cycle in the list and return its starting point
• Merge two sorted lists
• Split a list into two lists where one has the even indices while other has the odd indices

Trees:

• Construct a BST from a sorted array
• All traversals
• BFS/DFS
• Check if a tree is balanced
• Check if two trees are mirror image of each other
• Find max path sum in the tree where negative nodes are possible
• Find the lowest common ancestor of 2 nodes in a tree

Backtracking:

• Find all permutations of an array
• Find all possible subsets of an array
• Convert numbers into words according to letters on an old phone keypad

Hashtables

• Keep track of multiple occurrences of an object

Dynamic programming:

• Given you can climb 1, 2, or 3 stairs in one step, how many ways can you reach the top?
• Djikstra's shortest path algorithm