为啥只有50分？？？

#include<bits/stdc++.h>
#define ll long long
using namespace std;
string str,ans;
int main(){
	cin>>str;
	for(int i=0;i<=str.size();i++){
		if(str[i]>='0'&&str[i]<='9') cout<<str[i];
		else if(str[i]>'9'&&str[i+1]>'9') cout<<str[i];
		else{
			for(int j=1;j<=str[i+1]-48;j++) cout<<str[i];
			i+=1;
		}
	}
	return 0;
}