#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

int main(){
	ordered_set<int>  s;
	s.insert(1);
    s.insert(2);
    s.insert(3);
    s.insert(4);
    cout << s.order_of_key(1) << endl; // the number of elements in the s less than 1
    cout << s.order_of_key(2) << endl; // the number of elements in the s less than 2
    cout << s.order_of_key(3) << endl; // the number of elements in the s less than 3
    cout << s.order_of_key(4) << endl; // the number of elements in the s less than 4
	cout << *s.find_by_order(0) << endl; // print the 0-th smallest number in s(0-based)
    auto it = s.find_by_order(1);
    cout << *it << endl;//3
}

#include<memory>
int main() {
    std::unique_ptr<int> up,up1;
    up = std::unique_ptr<int>(new int(20));
    up1 = std::unique_ptr<int>(std::move(up));

    std::cout<<*up1<<std::endl; //结果：20
}

//iterative version
for(int mask = 0; mask < (1<<N); ++mask) {
	dp[mask][-1] = A[mask];	
    //handle base case separately (leaf states)
	for(int i = 0;i < N; ++i){
		if(mask & (1<<i))
			dp[mask][i] = dp[mask][i-1] + dp[mask^(1<<i)][i-1];
		else
			dp[mask][i] = dp[mask][i-1];
	}
	F[mask] = dp[mask][N-1];
}

//memory optimized, super easy to code.
for(int i = 0; i<(1<<N); ++i)
	F[i] = A[i];
for(int i = 0;i < N; ++i) {
    for(int mask = 0; mask < (1<<N); ++mask){
        if(mask & (1<<i))
            F[mask] += F[mask^(1<<i)];
    }
}