Book Image

C++ Data Structures and Algorithm Design Principles

By : John Carey, Anil Achary, Shreyans Doshi, Payas Rajan
Book Image

C++ Data Structures and Algorithm Design Principles

By: John Carey, Anil Achary, Shreyans Doshi, Payas Rajan

Overview of this book

C++ is a mature multi-paradigm programming language that enables you to write high-level code with a high degree of control over the hardware. Today, significant parts of software infrastructure, including databases, browsers, multimedia frameworks, and GUI toolkits, are written in C++. This book starts by introducing C++ data structures and how to store data using linked lists, arrays, stacks, and queues. In later chapters, the book explains the basic algorithm design paradigms, such as the greedy approach and the divide-and-conquer approach, which are used to solve a large variety of computational problems. Finally, you will learn the advanced technique of dynamic programming to develop optimized implementations of several algorithms discussed in the book. By the end of this book, you will have learned how to implement standard data structures and algorithms in efficient and scalable C++ 14 code.
Table of Contents (11 chapters)

Johnson's Algorithm

Having compared the relative merits and disadvantages of the Bellman-Ford algorithm and Dijkstra's algorithm, we will now discuss an algorithm that combines both of them to retrieve the shortest paths between every pair of vertices in a graph. Johnson's algorithm provides us with the advantage of being able to utilize the efficiency of Dijkstra's algorithm while still producing correct results for graphs with negative edge weights.

The concept behind Johnson's algorithm is quite novel – to contend with Dijkstra's limitations when dealing with negative weights, Johnson's algorithm simply reweights the edges in the graph so they are uniformly non-negative. This is accomplished with the rather creative use of Bellman-Ford combined with some particularly elegant mathematical logic.

The first step in Johnson's algorithm is to add a new 'dummy' vertex to the graph, which is subsequently connected to every other vertex...