题解 | 树查找

#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n;
    while (cin >> n) {
        vector<int>v(n + 1);
        for (int i = 1; i <= n; ++i) {
            cin >> v[i];
        }
        cin >> n;
        if (n == 1) {
            cout << v[1] << endl;
        }
        else {
            int index = 0;
            int s = 1;
            for (int i = 1; i < n; ++i) {
                index += s;
                s *= 2;
            }
            index += 1;
            s = s * 2;
            if(index>v.size()-1){
                cout<<"EMPTY"<<endl;
                continue;
            }
            cout << v[index];
            for (int i = index + 1; i < s && i < v.size()-1; ++i) {
                cout << " " << v[i];
            }
        }
    }
}
// 64 位输出请用 printf("%lld")