题解 | skew数

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

int main() {
    string str;
    while (cin >> str) {
        vector<int>v;
        for (int i = str.size() - 1; i >= 0; i--) {
            v.push_back(str[i] - '0');
        }
        int res = 0;
        for (int i = 0, k = 2; i < v.size(); i++, k *= 2) {
            if (v[i] != 0) {
                res += v[i] * (k - 1);
            }
        }
        cout << res << endl;
    }
}
// 64 位输出请用 printf("%lld")