题解

#include<iostream>
#include<string>
using namespace std;
int main(){
    string s,b[3]={"","00","0"};
    cin>>s;
    s=b[s.size()%3]+s;
    for(int i=0;i<s.size();i+=3){
        int x=0;
        if(s[i+2]=='1')x+=1;
        if(s[i+1]=='1')x+=2;
        if(s[i]=='1')x+=4;
        cout<<x;
    }
    return 0;
}