《Programming Abstractions in C》学习第66天，p235-p241总结。

一、技术总结

1.backtracking algorithm(回溯算法)

(1)定义

p236, For many real-world problem, the solution process consits of working your way

through a sequence of decision points in which each choic leads you further along

some path. If you make the correct set of choices, you end up at the solution. On the

other hand, if reach a dead end or otherwise discover you have made an

incorrect choice somewhere along the way, you have to backtrack to a precious

decision point and try a different path. Algorithm that use this approach are called

backtracking algorithm.

根据书中的定义，应用了“这种方法(approach)”的算法称为回溯算法。那么，“这种方法(approach)”是什么样的方法呢？这种方法是：发现当前决策错误的时候，回溯到之前的某个决策点(a previous decision point)，选择其它路径(try a different path)。

问题：a previsou decision point是指之前的某一个决策点，还是上一个决策点。

二、英语总结

1.decision point用法

答：意思是“决策点”。p236, For many real-world problem, the solution process consits of working your way through a sequence of decision points in which each choic leads you further along some path。

2.be home free是什么意思？

答：to be certain to succeed at sth because you have done the most difficult part of it(胜券在握)。

3.vantage point是什么意思？

答：a state, position, or opportunity affording superiority or advantage，优势。vantage多用于与sight(视野)相关的场景。“vantage point”: a place, especially a high place, that provides a good, clear view of an area(有利地位)。