# Thinking about efficiency

This article is going to cover a typical interview test question, which asks you to find the missing number in an array. The array is N elements in size and contains all the numbers 1 to N. The numbers can be in any order but will never repeat. One of the numbers is missing and your task is to find the missing number as efficiently as possible. There are a number of different ways we could tackle this problem, which we’re going to explore. The focus of this article isn’t so much about how to solve this problem and more about the (in)efficiency of different algorithms we might use.

# Reversing a linked list

Linked lists are an interviewers favourite subject matter. Whilst they are pretty easy to understand, at least in principle, they do require a little bit of brain warping to get your head around what’s going on under the hood. Of the common questions about linked lists I’ve come across, this quiz tackles the most common: how to reverse a linked list.

# C++ Smart pointers

This article is a discussion on smart pointers, what they are and why they are important to C++ programmers. Following the primary discussion I present a simple implementation of a reference counted smart pointer and show a simple example of using it. Although this article does not go into detail about how to develop a reference counted smart pointer the example code at the end is very well commented and that should be enough to aid understanding.

# Coding the Fibonacci Sequence

## Introduction

In this tutorial we’re going to look at how to calculate the Fibonacci numbers in code. We’ll use two different approaches to this, iterative and recursive, and we’ll examine the pros and cons of both. This tutorial assumes you already know what the Fibonacci numbers are and so I make no attempt to explain the maths behind them.