11988 - Broken Keyboard (a.k.a. Beiju Text), uva

#include<iostream>
#include<cstdio>
#include<deque>
#define db(a) cout << #a << " = " << a << endl
using namespace std;
deque<string> deq;
void insert(bool pos, string &s) {
 if (pos) deq.push_back(s);
 else deq.push_front(s);
 s = "";
}
int main() {
 string aux;
 bool end = true;
 char c;
 while (c = getchar()) {
  if (c == EOF) break;
  if (c == '\n') {
   insert(end, aux);
   while (deq.size()) { 
    printf("%s", deq.front().c_str());
    deq.pop_front();
   }
   printf("\n");
   deq.clear();
   aux = "";
   end = true;
  }
  else
   if (c == '[') {
    if (aux != "") {
     insert(end, aux);
    }
    end = false;
   }
   else
    if (c == ']') {
     if (aux != "") insert(end, aux);
     end = true;
    }
    else aux += c;
 }
 return 0;
}