Interview Cake by Aced
Interview Cake by Aced
We've all been there. You're 20 minutes into your PHP coding interview and you get hit with one of those hardcore data structures and algorithms questions. Binary trees, sorting, searching, queues, stacks...yikes.
But here's the thing: those interview questions don't have to take you off guard. It's possible to get really good at those classic data structures and algorithms coding interview questions.
Better yet, it doesn't take nearly as long as you think. At least, not the way we teach it. Because here on Interview Cake, with each interview question we don't just teach you the answer—we teach you the underlying algorithmic patterns at play, so you can use them to answer other coding interview questions in the future. In other words, we teach a way of thinking.
Try it out on these PHP programming interview questions. Each of them has answers, as well as explanations of how we got the answers and how you can apply that same approach to other problems in the future.
Write a function that finds the corresponding closing parenthesis given the position of an opening parenthesis in a string. keep reading »
Check whether a string's brackets, braces, and parentheses are properly nested and closed: the valid parentheses problem, solved step by step in O(n) time. keep reading »
Check if any permutation of an input string is a palindrome. keep reading »
Write a recursive function of generating all permutations of an input string. keep reading »
Efficiently sort numbers in an array, where each number is below a certain maximum. keep reading »
Find the repeat number in an array of numbers. Optimize for runtime. keep reading »
You're building a word cloud. Write a function to figure out how many times each word appears so we know how big to make each word in the cloud. keep reading »
Write code to continually track the max, min, mean, and mode as new numbers are inserted into a tracker class. keep reading »
Write a function to see if a binary tree is 'superbalanced'--a new tree property we just made up. keep reading »
Check whether a binary tree is a valid binary search tree. Avoid the common gotcha and solve it in O(n) time. A classic interview question, step by step. keep reading »
Find the second largest element in a binary search tree. keep reading »
Computer the nth Fibonacci number. Careful--the recursion can quickly spin out of control! keep reading »
Check whether a singly linked list has a cycle, using only O(1) additional space. A classic coding interview question, with a step-by-step solution. keep reading »
Count the number of ways to make an amount of money from a set of coin denominations (the number-of-ways version of coin change). Step-by-step solution. keep reading »
Implement a queue with two stacks. Assume you already have a stack implementation. keep reading »
Find the area of overlap between two rectangles. In the name of love. keep reading »
Write a function to delete a node from a linked list. Turns out you can do it in constant time! keep reading »
Reverse a singly linked list in place and return the new head, in O(n) time and O(1) space. A classic interview question, solved step by step. keep reading »
Find the kth to last node in a singly linked list in O(n) time and O(1) space, a cousin of removing the nth node from the end. Step-by-step solution. keep reading »
Write a function to reverse a string in place. keep reading »
Write a function to reverse the word order of a string, in place. It's to decipher a supersecret message and head off a heist. keep reading »
I'm making a new search engine called MillionGazillion(tm), and I need help figuring out what data structures to use. keep reading »
Given an array of numbers in sorted order, how quickly could we check if a given number is present in the array? keep reading »
Find the rotation point (the smallest item) in a rotated sorted array in O(lg n) time. A classic coding interview problem, with a step-by-step solution. keep reading »
Given a flight length and a list of movie lengths, find two movies that add up to exactly the flight length: a real-world two sum problem, in O(n) time. keep reading »
Maximize the value of cakes that fit in a bag when you can take unlimited copies of each: the unbounded knapsack problem, solved step by step. keep reading »
Given yesterday's stock prices, find the max profit from one buy and one sell. A classic interview problem, solved in O(n) time and O(1) space. keep reading »
Given an array of integers, return an array where each item is the product of all the others, without division, in O(n) time. Step-by-step solution. keep reading »
Find the highest possible product that you can get by multiplying any 3 numbers from an input array. keep reading »
Merge overlapping meeting time ranges into condensed blocks: the classic merge intervals problem, with a step-by-step O(n lg n) solution. keep reading »
Implement a stack with a get_max method that returns the largest item in O(1) time: the max stack problem, with a step-by-step solution. keep reading »
Every ID appears twice except one. Find the unique one in O(n) time and O(1) space: the single number problem, with a step-by-step solution. keep reading »
Do an in-place shuffle on an array of numbers. It's trickier than you might think! keep reading »
Write a function to tell us if cafe customer orders are served in the same order they're paid for. keep reading »
Given a 7-sided die, make a 5-sided die. keep reading »
Given a 5-sided die, make a 7-sided die. keep reading »
A building has 100 floors. Figure out the highest floor an egg can be dropped from without breaking. keep reading »
Figure out which number is repeated. But here's the catch: optimize for space. keep reading »
Figure out which number is repeated. But here's the catch: do it in linear time and constant space! keep reading »
Your friend copied a bunch of your files and put them in random places around your hard drive. Write a function to undo the damage. keep reading »
Design a ticket sales site like Ticketmaster: scope the requirements, model events, seats, and orders, and handle traffic spikes when tickets go on sale. keep reading »
