RT,我也不知道为什么

/*
%% The Second Coming Orz
*/
#include<iostream>
#include<cstdio>
#include<string>

using namespace std;

string sol()
{
	int n;
	string c,s="";
	char ch;
	while(cin>>ch)
	{
		if(ch=='[')
		{
			cin>>n;
			c=sol();
			for(int i=0;i<n;i++)s+=c;
		}
		else if(ch==']')return s;
		else s+=ch;
	}
}
int main()
{
	cout<<sol();
	return 0;
}

Thanks♪(･ω･)ﾉ