新手求助

P8824终端

样例过了但是提交后都是WA 为啥啊qaq

#include <bits/stdc++.h>
using namespace std;
int n;
string a,b,c;
string ans[1000001];
int i;
bool flag[1000001];
int main()
{
	cin >> n;
	while(n > 0)
	{
		cin >> a;
		if(a == "touch")
		{
			cin >> b;
			ans[i] = b;
			i++;
		}
		else if(a == "rm")
		{
			cin >> b;
			int ii = 0;
			while(ii < i)
			{
				if(ans[ii] == b)
					ans[ii] = " ";
				ii++;
			}
		}
		else if(a == "ls")
		{
			int ii = 0;
			while(ii < i)
			{
				if(ans[ii] != " ")
					cout << ans[ii] << endl;
				ii++;	
			}
			return 0;
		}
		else if(a == "rename")
		{
			int ii = 0;
			cin >> b >> c;
			while(ii < i)
			{
				if(ans[ii] == b)
				{
					ans[ii] = c;					
					break;
				}
				ii++;
			}
		}
	}
}