字符串的用法; 简洁精妙
#include<iostream>
#include<cstring>
using namespace std;
int main(){
string s, res;
cin>>s;
for(int i = 0; i<s.size(); i++){
if(i+1<s.size() && s[i+1]<='9'){
int k = s[i+1] - '0';
while(k -- ) res += s[i];
i ++ ;//这一位是数字,跳过
}
else res += s[i];
}
cout<<res;
return 0;
}