"""
实战题目
https://leetcode-cn.com/problems/climbing-stairs/
https://leetcode-cn.com/problems/generate-parentheses/
https://leetcode-cn.com/problems/n-queens
https://leetcode-cn.com/problems/valid-sudoku/description/
https://leetcode-cn.com/problems/sudoku-solver/#/description

实战题目
https://leetcode-cn.com/problems/word-ladder/
https://leetcode-cn.com/problems/minimum-genetic-mutation/
课后作业
总结双向 BFS 代码模版，请同学们提交在第 6 周学习总结中。
参考链接
A* 代码模板
相似度测量方法
二进制矩阵中的最短路径的 A* 解法
8 puzzles 解法比较
实战题目
https://leetcode-cn.com/problems/shortest-path-in-binary-matrix/
https://leetcode-cn.com/problems/sliding-puzzle/
https://leetcode-cn.com/problems/sudoku-solver/
"""
