3227. 声控开关 (Hard)

    int judge = pow(2, n);
    if(judge - 1 != k % judge) cout<<"OFF"<<endl;
    else cout<<"ON"<<endl;
}

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

int main() {
    int num;
    cin >> num;
    for (int l = 1; l <= num; ++l) {
        int n, k;
        cin >> n >> k;
        int temp = 1;
        for (int i = 1; i <= n; ++i) {
            if ((k & (int)(pow(2, i) - 1)) != (int)(pow(2, i) - 1)) {
                temp = 0;
                break;
            }
        }

        if (temp) {
            cout << "Case " << l << ": ON" << endl;
        }
        else {
            cout << "Case " << l << ": OFF" << endl;
        }
    }
    return 0;
}