题解在此

#include <iostream>
#include <algorithm>
#include <cmath>
using namespace std;
int main(){
    string s;
    cin>>s;
    int size=s.size();
    if (size<8){
        for (int i=1;i<=8-size;i++){
            s='0'+s;
        }
        size=8;
    }else if (size<16){
        for (int i=1;i<=16-size;i++){
            s='0'+s;
        }
        size=16;
    }else if (size<32){
        for (int i=1;i<=32-size;i++){
            s='0'+s;
        }
        size=32;
    }
    reverse(s.begin(),s.end());
    long long sum=0,cnt=size-1;
    for (int i=0;i<size;i++){
        sum+=(s[i]-'0')*pow(2,cnt);
        cnt--;
    }
    cout<<sum;
    return 0;
}