pbds.cpp

https://codeforces.com/blog/entry/11080


#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;



//1. using it as ordered set
typedef tree<long long, null_type, less<long long>, rb_tree_tag, tree_order_statistics_node_update> pbds; 
// *find_by_order(k-1th) 
// order_of_key(val)
// any.erase(val)


//2.using it as ordered multiset
typedef tree<long long, null_type, less_equal<long long>, rb_tree_tag, tree_order_statistics_node_update> pbds; 

// Some points to take care for ordered multiset

1. don't use any.find() // it will always return end
2. lower_bound works like upper_bound
3. upper_bound works like lower bound
4. any.erase(any.find_by_order(any.order_of_key(val))); // use this for deleting

https://www.codechef.com/viewsolution/74496520