《算法导论》第一章-第1节_练习（参考答案）

算法导论（第三版）参考答案：练习1.1-1，练习1.1-2，练习1.1-3，练习1.1-4，练习1.1-5

Exercise 1.1-1

Give a real-world example that requires sorting or a real-world example that requires computing a convex hull.

排队问题：小学体育课上，老师要求我们由低到高站成一列。

防线修建：在经费有限的情况下，尽可能多的包含自己的城市。

Exercise 1.1-2

Other than speed, what other measures of efficiency might one use in a real-world setting?

资源利用率、内存占用情况。

Exercise 1.1-3

Select a data structure that you have seen previously, and discuss its strengths and limitations.

链表

优势：可变长度、不需要连续内存空间。

局限：查询某元素，需要遍历链表、需要多余的空间存放指针。

Exercise 1.1-4

How are the shortest-path and traveling-salesman problems given above similar? How are they different?

相似之处在于都是在寻找最短路径。

区别在于，最短路径问题是在给定两坐标后，寻找之间的实际路径长短最短的路线；而旅行商问题是需要遍历所有的地点后，最终回到起点的最短路线。

Exercise 1.1-5

Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough.

如果你女朋友不喜欢香菜，那么在你俩的烛光晚餐中，必须不能有一点香菜。不然你的计划就泡汤了！

如果你的朋友不喜欢香菜，那么在一起出去聚餐时，碰巧点了一个上面撒了香菜的蛋羹。情况会好很多。