代写C++作业，实现多线程BFS搜索

Introduction

In this assignment you will perform a parallel breadth-first search (BFS) of the 4×3 Sliding Tile state space. The result of this search will be that the distance of every state in the state space from the initial configuration will be stored in an array. In C++ you can only access items in an array using an integer offset. Thus, we cannot directly map between our Sliding Tile puzzle class and an element in the depth array. Luckily, there is a 1-to-1 mapping between states in the puzzle and integers between 0 and 12!/2. We can perform this mapping using what are called “Ranking” and “Unranking” functions. A ranking function will convert a state into an integer, and an unranking function will convert an integer into the corresponding state. T