我需要一个用于标准GCC STL地图容器的订单统计树。
I need an order statistic tree for standard GCC STL map containers.
我检查过，有一种称为PBDS的东西。基于策略的数据结构。任何人都可以告诉我如何使用STL地图容器进行订单统计树的使用。
I checked and there is something known as PBDS. Policy based data structures. That usage is also not clear to me.
即使它仅在GNU G ++上它足够？
Anyone can tell me how to use STL map containers for order statistic tree? Even if its only on GNU G++ its enough?
推荐答案以下是以执行订单统计的GNU基于策略的STL MAP为例树（在Linux gcc 4.6.1上测试）：
Here is the example of GNU Policy-Based STL MAP implemented as order statistic tree (tested on Linux gcc 4.6.1):
#include <iostream> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace std; using namespace __gnu_pbds; typedef tree< int, int, less<int>, rb_tree_tag, tree_order_statistics_node_update> map_t; int main() { map_t s; s.insert(make_pair(12, 1012)); s.insert(make_pair(505, 1505)); s.insert(make_pair(30, 1030)); cout << s.find_by_order(1)->second << '\n'; return 0; }这里是链接到GNU基于政策的数据结构概述。以下是其他 tree_order_statistics示例。我找不到基于策略的数据结构的良好参考，但您可以使用这些链接以及PBDS源。
Here is a link to the overview of GNU Policy-Based Data Structures. Here is other tree_order_statistics example. I cannot find a good reference for Policy-Based Data Structures, but you can use these links as well as PBDS sources.