当提前知道大小时，初始化std :: map [英] Initializing a std::map when the size is known in advance

问题描述

我想初始化一个 std :: map 。现在我使用 :: insert ，但是我觉得我在浪费一些计算时间，因为我已经知道我想要分配的大小。有没有办法分配固定大小的地图，然后填写地图？

I would like to initialize a std::map. For now I am using ::insert but I feel I am wasting some computational time since I already know the size I want to allocate. Is there a way to allocate a fixed size map and then fill the map ?

推荐答案

不，地图的成员在内部存储在树结构中。在知道要存储的键和值之前，没有办法构建树。

No, the members of the map are internally stored in a tree structure. There is no way to build the tree until you know the keys and values that are to be stored.

这篇关于当提前知道大小时，初始化std :: map的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！