C++中的订单统计树

2021-12-22 00:00:00 algorithm data-structures c++ stl

我需要标准 GCC STL 地图容器的订单统计树.

I need an order statistic tree for standard GCC STL map containers.

我查了一下，有一种叫做 PBDS 的东西.基于策略的数据结构.我也不清楚这种用法.

I checked and there is something known as PBDS. Policy based data structures. That usage is also not clear to me.

谁能告诉我如何将 STL 映射容器用于订单统计树?即使它只在 GNU G++ 上就足够了吗?

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

以下是将 GNU Policy-Based STL MAP 实现为订单统计树的示例(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 << '
';
  return 0;
}

这里是基于 GNU 策略的数据结构概述的链接.这是其他 tree_order_statistics 示例.我找不到有关基于策略的数据结构的好的参考资料，但您可以使用这些链接以及 PBDS 来源.

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.

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