#include <iostream>
#include <string>
#include <set>
using namespace std;
int main(){
	auto cmp = [](auto a, auto b){
		return a > b;
	};
	set<int> a;
	set<int> b = {1, 5, 4, 3, 3, 2};
	set<int, decltype(cmp)> c(cmp);
	a.insert(1);a.insert(5);a.insert(3);a.insert(2);
	c.insert(1);c.insert(5);c.insert(3);c.insert(2);
	a.emplace(6);
	for(auto x : a){
		cout << x << " ";
	}
	cout << endl;
	for(auto x : c){
		cout << x << " ";
	}
	cout << endl;
	cout << a.count(3) << endl;
	a.erase(6);
	for(auto it = a.begin(); it != a.end(); it++){
		cout << *it << " ";
	}
	//From "Smaller" To	"Bigger", To compare big, we need "func:cmp"
	cout << endl;
	cout << *(c.find(5))<< endl;
	//lower_bound : >= val ; upper_bound : > val ;
	cout << *(c.lower_bound(2)) << " " << *(c.upper_bound(2)) << endl;
	cout << *(a.lower_bound(2)) << " " <<*(a.upper_bound(2)) << endl;
	return 0;
}
/*
COUT
1 2 3 5 6
5 3 2 1
1
1 2 3 5
5
2 1
2 3
*/