UVA 11988(p143)----Broken Keyboard

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
char st[100010];
int main()
{
while(scanf("%s",st)!=EOF)
{
int i=0;
deque<int> q;
int l=strlen(st);
while(st[i]=='['||st[i]==']') i++;
q.push_front(i);
while(i<l)
{
if(st[i]=='[')
{
q.push_front(i+1);
st[i]='\0';
}
else
if(st[i]==']')
{
q.push_back(i+1);
st[i]='\0';
}
i++;
}
while(!q.empty())
{
printf("%s",st+q.front());
q.pop_front();
}
printf("\n");
}
return  0;
}