Google Interview Hacks

What is the "data structure brainstorm" approach to solving a technical question? Answer: Run through a list of data structures and try to apply each one.

What is the "base case and build" approach to solving a technical question? 1. Solve the problem first for a base case (e.g. n = 1). 2. Solve the problem for the next case, assuming the answer for the previous (base) case is already known (e.g. n = 2). 3. Continue solving the problem for each next case (e.g. n = 3... 4... etc) until able to create a solution that uses previous cases to solve the current case.

What is the simplify and generalize approach to solving a technical question? Implement a multi-step approach. First, change a constraint such as the data type or amount of data (simplify the problem). Then, solve the new simplified version of the problem. Finally, using the algorithm for the simplified version of the problem, generalize the problem and adapt the algorithm for the simplified version to apply to the complex version.

What is the pattern matching approach to solving a technical question? Answer: Consider what problems the algorithm is similar to and try to modify the solution to the related problem to develop an algorithm for this problem.

What is the examplify approach to solving a technical question? Under exemplify, you write out specific examples of the problem and see if you can derive a general rule from there.

What are the five approaches you can use to solve a technical question? 1. Examplify 2. Pattern Matching 3. Simplify and Generalize 4. Base Case and Build 5. Data Structure Brainstorm

What are the five steps you should follow when solving a technical question? 1. Ask your interviewer questions to resolve ambiguity 2. Design an algorithm. 3. Write pseudocode first, but make sure to tell your interviewer that you'll eventually write "real" code. 4. Write your code at a moderate pace. 5. Test your code and carefully fix any mistakes.

What are the exact values of the following powers of 2? What are the approximate values? If unit is Bytes, what is the approximation of those bytes to MB, GB or other nearest unit? 2¹⁰ 2²⁰ 2³⁰ 2⁴⁰ Answer: 2¹⁰ = 1024 ≈ 1 thousand ≈ 1K 2²⁰ = 1,048,576 ≈ 1 million ≈ 1MB 2³⁰ = 1,073,741,824 ≈ 1 billion ≈ 1GB 2⁴⁰ = 1,099,511,627,776 ≈ 1 trillion ≈ 1TB

What are the exact values of the following powers of 2? If exact value is the number of bytes, what would be an approximation of those bytes to MB, GB, or other nearest unit? 2¹⁶ 2³² Answer: 2¹⁶ = 65,536 ≈ 64K 2³² = 4,294,967,296 ≈ 4GB

What are the exact values of the following powers of 2? 2⁷ 2⁸ Answer: 2⁷ = 128 2⁸ = 256

What concepts should you be familiar with? Bit Manipulation Singleton Design Pattern Factory Design Pattern Memory (Stack vs. Heap) Recursion Big-O Time

What algorithms should you be familiar with? Breadth First Search Depth First Search Binary Search Merge Sort Quick Sort Tree Methods (Insert/Find/etc.)

What data-structures should you be familiar with? Linked Lists Binary Trees Tries Stacks Queues Vectors/ArrayLists Hash Tables