Introduction

In this blog post, we'll share the most commonly asked coding interview questions at Valve. If you don't have months to study for your interviews, you can use AI tools like Chatmagic to generate solutions quickly and efficiently - helping you pass the interviews and get the job offer!

Problem #1: String to Integer (atoi)

Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer. The algorithm for myAtoi(string s) is as follows: Whitespace: Ignore any leading whitespace (" "). Signedness: Determine the sign by checking if the next character is '-' or '+', assuming positivity if neither present. Conversion: Read the integer by skipping leading zeros until a non-digit character is encountered or the end of the string is reached. If no digits were read, then the result is 0. Rounding: If the integer is out of the 32-bit signed integer range [-231, 231 - 1], then round the integer to remain in the range. Specifically, integers less than -231 should be rounded to -231, and integers greater than 231 - 1 should be rounded to 231 - 1. Return the integer as the final result. Example 1: Input: s = "42" Output: 42 Explanation: The underlined characters are what is read in and the caret is the current reader position. Step 1: "42" (no characters read because there is no leading whitespace) ^ Step 2: "42" (no characters read because there is neither a '-' nor '+') ^ Step 3: "42" ("42" is read in) ^ Example 2: Input: s = " -042" Output: -42 Explanation: Step 1: " -042" (leading whitespace is read and ignored) ^ Step 2: " -042" ('-' is read, so the result should be negative) ^ Step 3: " -042" ("042" is read in, leading zeros ignored in the result) ^ Example 3: Input: s = "1337c0d3" Output: 1337 Explanation: Step 1: "1337c0d3" (no characters read because there is no leading whitespace) ^ Step 2: "1337c0d3" (no characters read because there is neither a '-' nor '+') ^ Step 3: "1337c0d3" ("1337" is read in; reading stops because the next character is a non-digit) ^ Example 4: Input: s = "0-1" Output: 0 Explanation: Step 1: "0-1" (no characters read because there is no leading whitespace) ^ Step 2: "0-1" (no characters read because there is neither a '-' nor '+') ^ Step 3: "0-1" ("0" is read in; reading stops because the next character is a non-digit) ^ Example 5: Input: s = "words and 987" Output: 0 Explanation: Reading stops at the first non-digit character 'w'. Constraints: 0 <= s.length <= 200 s consists of English letters (lower-case and upper-case), digits (0-9), ' ', '+', '-', and '.'.

Topics: String

Problem #3: Design Parking System

Design a parking system for a parking lot. The parking lot has three kinds of parking spaces: big, medium, and small, with a fixed number of slots for each size. Implement the ParkingSystem class: ParkingSystem(int big, int medium, int small) Initializes object of the ParkingSystem class. The number of slots for each parking space are given as part of the constructor. bool addCar(int carType) Checks whether there is a parking space of carType for the car that wants to get into the parking lot. carType can be of three kinds: big, medium, or small, which are represented by 1, 2, and 3 respectively. A car can only park in a parking space of its carType. If there is no space available, return false, else park the car in that size space and return true. Example 1: Input ["ParkingSystem", "addCar", "addCar", "addCar", "addCar"] [[1, 1, 0], [1], [2], [3], [1]] Output [null, true, true, false, false] Explanation ParkingSystem parkingSystem = new ParkingSystem(1, 1, 0); parkingSystem.addCar(1); // return true because there is 1 available slot for a big car parkingSystem.addCar(2); // return true because there is 1 available slot for a medium car parkingSystem.addCar(3); // return false because there is no available slot for a small car parkingSystem.addCar(1); // return false because there is no available slot for a big car. It is already occupied. Constraints: 0 <= big, medium, small <= 1000 carType is 1, 2, or 3 At most 1000 calls will be made to addCar

Topics: Design, Simulation, Counting