题解 | #skew数#

#include <iostream>
#include <math.h>
using namespace std;

int main() {
    string str;
    while (cin>>str) {
        int sum = 0,i,j,len = str.length();
        for(i=len-1,j=0;i>=0&&j<len;i--,j++){
            sum += (str[i]-'0')*(pow(2, j+1)-1);
        }
        cout<<sum<<endl;
    }
}