题解 | #排列与二进制#

#include <iostream>

using namespace std;

int main() {
    int n, m;
    while (cin >> n >> m) {
        if (!n && !m)
            break;
        int sum = 0;
        for (int i = 0; i < m; ++i) {
            int k = n - i;
            while (!(k & 1)) {
                k >>= 1;
                sum++;
            }
        }
        cout << sum << endl;
    }
}

简洁的位运算