L1-017. 到底有多二

//AC

#include <iostream>#include <cstdlib>#include <stdio.h>#include <algorithm>#include <math.h>#include <string.h>#include <queue>#include <stack>#include <vector>#include <map>#include <set>typedef long long ll;using namespace std;int main(){    string s;    float sum;    int k;    cin>>s;    if(s[0]=='-'){        k=0;        for (int i=1; i<s.size(); i++) {            if(s[i]-'0'== 2){                k++;            }        }        sum=(k*1.5)/(s.size()-1);        if(s[s.size()-1]%2==0){            sum=sum*2.0;        }            }    else{        k=0;         for (int i=0; i<s.size(); i++) {             if(s[i]-'0'== 2){                 k++;             }         }        sum=(k*1.0)/s.size();        if(s[s.size()-1]%2==0){            sum=sum*2.0;        }    }    sum=sum*100;    printf("%.2f",sum);cout<<"%"<<endl;        return 0;}