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Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
* Array and string manipulation
Solve merging-ranges Write a function to merge meeting times. Added an in-place solution, which the "Bonus" section suggested attempting to solve. - Added some simple benchmarks to test the performance differences between the in-place and not-in-place variants. To my surprise, the in-place solution was consistently slower than the not-in-place solution.
2020-02-13 15:52:20 +01:00
** DONE Merging Meeting Times
Complete InterviewCake reverse-string-in-place Wrote a function in TypeScript to reverse an array of characters mutatively.
2020-02-12 16:53:21 +01:00
** DONE Reverse String in Place
Solve InterviewCake's reverse-words Wrote a function to reverse the words in a list of characters. A word is a space-delimited strings of characters. The trick here is to first reverse the entire string and then reverse each word individually.
2020-02-18 15:17:59 +01:00
** DONE Reverse Words
Solve InterviewCake's merge sorted arrays question Write a function merging two sorted arrays into one sorted array.
2020-02-19 17:02:38 +01:00
** DONE Merge Sorted Arrays
Solve InterviewCake's cafe-order-checker problem Write a predicate that tests if a given list of integers, zs, is a possible interleaving of two other lists, xs and ys.
2020-02-20 16:20:58 +01:00
** DONE Cafe Order Checker
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
* Hashing and hash tables
Solve InterviewCake's inflight-entertainment problem Write a predicate that tests whether two films in a list of films can exactly fill the duration of a flight.
2020-02-21 12:30:01 +01:00
** DONE Inflight Entertainment
Solve InterviewCake permutation-palindrome problem Write a predicate to test whether any permutation of an input string is a palindrome.
2020-02-24 17:24:16 +01:00
** DONE Permutation Palindrome
Solve InterviewCake's word-cloud problem Write a function to count the frequency of words in a sentence. Ignore casing for words; ignore punctuation.
2020-02-26 16:46:02 +01:00
** DONE Word Cloud Data
Solve InterviewCake's top-scores Using a counting sort to sort a list of values in linear time.
2020-02-26 17:03:50 +01:00
** DONE Top Scores
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
* Greedy Algorithms
Solve InterviewCake's stock-price problem Write a function that returns the maximum profit that a trader could have made in a day. I solved this using a greedy algorithm which constantly sets the maximum profit by tracking the lowest price we've encountered.
2020-02-27 16:37:36 +01:00
** DONE Apple Stocks
Solve InterviewCake's highest-product-of-3 Write a function that returns the highest product of three integers within a list of integers. This solution uses a greedy algorithm that solves for the answer in linear time. The space complexity is constant.
2020-03-01 22:30:25 +01:00
** DONE Highest Product of 3
Solve InterviewCake's product-of-other-numbers This problem challenged me: without using division, write a function that maps a list of integers into a list of the product of every integer in the list except for the integer at that index. This was another greedy algorithm. The take-away is to first solve the problem using brute force; this yields an algorithm with O(n*(n-1)) time complexity. Instead of a quadratic time complexity, a linear time complexity can be achieved my iterating over the list of integers twice: 1. Compute the products of every number to the left of the current number. 2. Compute the products of every number to the right of the current number. Finally, iterate over each of these and compute lhs * rhs. Even though I've solved this problem before, I used InterviewCake's hints because I was stuck without them. I should revisit this problem in a few weeks.
2020-03-02 17:45:15 +01:00
** DONE Product of All Other Numbers
Implement an in-place shuffling algorithm I believe this may be the Fisher-Yates shuffle, but I'm not sure.
2020-03-06 18:54:15 +01:00
** DONE Cafe Order Checker
** DONE In-Place Shuffle
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
* Sorting, searching, and logarithms
Solve InterviewCake's "find rotation point" problem Write a function that accepts a rotated cycle of alphabetically sorted strings and returns the index what should be the first element if the elements were not rotated.
2020-03-09 18:13:26 +01:00
** DONE Find Rotation Point
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
** TODO Find Repeat, Space Edition
Solve InterviewCake's top-scores problem Write a function to sort a list of scores for a game in linear time. While I had previously solved this in python, I hadn't marked the todo.org file, so I ended up doing this again. "Perfect practice makes perfect."
2020-03-13 17:51:38 +01:00
** DONE Top Scores
Mark duplicate InterviewCake questions as DONE I wrongfully assumed that the relationship between a question and a question category was one-to-one; it is actually one-to-many. This explains why I completed the "Cafe Order Checker" and "Top Scores" questions twice. I'm marking the questions that I've completed as DONE because I would prefer to do every question once and then prioritize repeating the questions with which I experienced difficulty.
2020-03-14 13:20:43 +01:00
** DONE Merging Meeting Times
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
* Trees and graphs
Solve InterviewCake's balanced-binary-tree problem Write a predicate for determining if a binary tree is "super balanced", which means that the depths of all of the tree's leaves are equal or differ by at most one.
2020-03-14 13:48:37 +01:00
** DONE Balanced Binary Tree
Solve InterviewCake's bst-checker problem Write a function that returns true if a given binary tree is a valid binary search tree (i.e. if all of root's left nodes are less than root.value, all of root's right nodes are greater than root.value, and both left and right subtrees are also valid binary search trees).
2020-03-16 00:09:29 +01:00
** DONE Binary Search Tree Checker
Solve InterviewCake's second-largest-item-in-bst Return a function that returns the second largest item in a binary search tree (i.e. BST). A BST is a tree where each node has no more than two children (i.e. one left child and one right child). All of the values in a BST's left subtree must be less than the value of the root node; all of the values in a BST's right subtree must be greater than the value of the root node; both left and right subtrees must also be BSTs themselves. I solved this problem thrice -- improving the performance profile each time. The final solution has a runtime complexity of O(n) and a spacetime complexity of O(1).
2020-03-16 12:45:34 +01:00
** DONE 2nd Largest Item in a Binary Search Tree
Solve InterviewCake's graph-coloring problem Write a function that colors the nodes of a graph such that no two neighbors share a color.
2020-03-19 13:31:24 +01:00
** DONE Graph Coloring
Solve InterviewCake.com's mesh-message problem Write a function that returns the shortest path between nodes A and B in an unweighted graph. I know two algorithms for finding the shortest path in a *weighted* graph: - Use a heap as a priority queue instead of the regular queue that you would use when doing a BFT. This is called Dijkstra's algorithm. You can also use Dijkstra's algorithm in an unweight graph by imaginging that all of the weights on the edges are the same value (e.g. 1). - Map the weighted graph into an unweighted graph by inserting N nodes between each node, X and Y, where N is equal to the weight of the edge between X and Y. After you map the weighted graph into an unweighted graph, perform a BFT from A to B. A BFT will always find the shortest path between nodes A and B in an unweighted graph. I had forgotten that a BFT in an unweighted graph will always return the shortest path between two nodes. I learned two things from InterviewCake.com's solution: 1. I remembered that a BFT in an unweighted graph will return the shortest path (if one exists). 2. I learned to use a dictionary to store the edge information and then back-tracking to reconstruct the shortest path.
2020-03-20 17:49:49 +01:00
** DONE MeshMessage
Solve InterviewCake's find duplicate beast mode Write a function to find a duplicate item in a list of numbers. The values are in the range [1, n]; the length of the list is n + 1. The solution should run in linear time and consume constant space. The solution is to construct a graph from the list. Each graph will have a cycle where the last element in the cycle is a duplicate value. See the solution for specific techniques on how to compute the length the cycle without infinitely looping.
2020-03-26 12:55:06 +01:00
** DONE Find Repeat, Space Edition BEAST MODE
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
* Dynamic programming and recursion
Solve InterviewCake's recursive string permutations problem Write a function that returns the set of all of the possible permutations of an input string. This function should be solved recursively.
2020-03-26 17:57:41 +01:00
** DONE Recursive String Permutations
Solve InterviewCake's compute nth Fibonacci While the "Dynamic programming and recursion" section hosts this problem, the optimal solution does not use recursion. Many cite the Fibonacci problem as a quintessential dynamic programming question. I assume these people expect an answer like: ```python def fib(n): cache = {0: 0, 1: 1} def do_fib(n): if n in cache: return cache[n] else: cache[n - 1] = do_fib(n - 1) cache[n - 2] = do_fib(n - 2) return cache[n - 1] + cache[n - 2] return do_fib(n) ``` The cache turns the runtime of the classic Fibonacci solution... ```python def fib(n): if n in {0, 1}: return n return fib(n - 1) + fib(n - 2) ``` ... from O(2^n) to a O(n). But both the cache itself and the additional stacks that the runtime allocates for each recursive call create an O(n) space complexity. InterviewCake wants the answer to be solved in O(n) time with O(1) space. To achieve this, instead of solving fib(n) from the top-down, we solve it from the bottom-up. I found this problem to be satisfying to solve.
2020-03-30 15:14:02 +02:00
** DONE Compute nth Fibonacci Number
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
** TODO Making Change
** TODO The Cake Thief
Solve InterviewCake's balanced-binary-tree problem Write a predicate for determining if a binary tree is "super balanced", which means that the depths of all of the tree's leaves are equal or differ by at most one.
2020-03-14 13:48:37 +01:00
** DONE Balanced Binary Tree
Solve InterviewCake's bst-checker problem Write a function that returns true if a given binary tree is a valid binary search tree (i.e. if all of root's left nodes are less than root.value, all of root's right nodes are greater than root.value, and both left and right subtrees are also valid binary search trees).
2020-03-16 00:09:29 +01:00
** DONE Binary Search Tree Checker
Solve InterviewCake's second-largest-item-in-bst Return a function that returns the second largest item in a binary search tree (i.e. BST). A BST is a tree where each node has no more than two children (i.e. one left child and one right child). All of the values in a BST's left subtree must be less than the value of the root node; all of the values in a BST's right subtree must be greater than the value of the root node; both left and right subtrees must also be BSTs themselves. I solved this problem thrice -- improving the performance profile each time. The final solution has a runtime complexity of O(n) and a spacetime complexity of O(1).
2020-03-16 12:45:34 +01:00
** DONE 2nd Largest Item in a Binary Search Tree
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
* Queues and stacks
** TODO Largest Stack
** TODO Implement A Queue With Two Stacks
** TODO Parenthesis Matching
** TODO Bracket Validator
* Linked lists
** DONE Delete Node
** TODO Does This Linked List Have A Cycle?
** TODO Reverse A Linked List
** TODO Kth to Last Node in a Singly-Linked List
Solve InterviewCake's find duplicate beast mode Write a function to find a duplicate item in a list of numbers. The values are in the range [1, n]; the length of the list is n + 1. The solution should run in linear time and consume constant space. The solution is to construct a graph from the list. Each graph will have a cycle where the last element in the cycle is a duplicate value. See the solution for specific techniques on how to compute the length the cycle without infinitely looping.
2020-03-26 12:55:06 +01:00
** DONE Find Repeat, Space Edition BEAST MODE
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
* System design
** TODO URL Shortener
** TODO MillionGazillion
** TODO Find Duplicate Files
* General programming
** TODO Rectangular Love
** TODO Temperature Tracker
* Bit manipulation
** TODO Binary Numbers
** TODO The Stolen Breakfast Drone
* Combinatorics, probability, and other math
** TODO Which Appears Twice
** TODO Find in Ordered Set
Mark duplicate InterviewCake questions as DONE I wrongfully assumed that the relationship between a question and a question category was one-to-one; it is actually one-to-many. This explains why I completed the "Cafe Order Checker" and "Top Scores" questions twice. I'm marking the questions that I've completed as DONE because I would prefer to do every question once and then prioritize repeating the questions with which I experienced difficulty.
2020-03-14 13:20:43 +01:00
** DONE In-Place Shuffle
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
** TODO Simulate 5-sided die
** TODO Simulate 7-sided die
** TODO Two Egg Problem
* JavaScript
** TODO JavaScript Scope
Remove HTML-encoded quote Prefer ' to '
2020-02-27 17:52:58 +01:00
** TODO What's Wrong with This JavaScript?
Encode InterviewCake.com questions as an org-mode list This way I can track what I've done and what I need to do.
2020-02-11 15:05:56 +01:00
* Coding interview tips
** TODO How The Coding Interview Works
** TODO General Coding Interview Advice
** TODO Impostor Syndrome
** TODO Why You Hit Dead Ends
** TODO Tips for Getting Unstuck
** TODO The 24 Hours Before Your Interview
** TODO Beating Behavioral Questions
** TODO Managing Your Interview Timeline
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