SGI STL (1) :: Use Proper Containers and Algorisms

最新推荐文章于 2017-11-04 17:00:30 发布

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本文通过一个具体的例子阐述了在软件开发中忽视复杂度可能带来的严重影响。例如，在使用STL vector容器时，如果忽略其复杂度而采用类似双向链表的数据结构实现，可能会导致访问速度大幅度降低，进而影响整体程序的性能。

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what complexity means

If you ignore it, the performance of the resulting program will often render it useless.

For example:
Consider the STL vector container. Ignoring the complexity specification, it is possible to implement vector using the same underlying data structure as list, i.e. as a doubly linked list. But for a vector of length 10,000, this would probably slow down an average computation of v[i] by something like a factor of 5,000.

For a program that requires many vector accesses, such as a typical numerical computation, this is likely to change an execution time of minutes to days.