链表 UVA 11988 Broken Keyboard (a.k.a. Beiju Text)

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 5;
struct Link_list    {
    char ch;
    Link_list *nex;
}link_list[N];

int main(void)  {
    while (true) {
         Link_list *head = link_list;
         Link_list *q = link_list + 1;
         head -> nex = NULL;
         Link_list *tail = head, *pos = head;
         char c;
         while (true)  {
            c = getchar ();
            if (c == ‘\n‘)  break;
            if (c == EOF)   return 0;
            if (c != ‘[‘ && c != ‘]‘) {
                Link_list *p = q++;
                p -> ch = c;
                p -> nex = pos -> nex;
                pos -> nex = p;
                pos = p;
                if (tail -> nex != NULL)    tail = pos;
            }
            else if (c == ‘[‘)  pos = head;
            else    pos = tail;
         }
         Link_list *p = head -> nex;
         while (p)   {
             printf ("%c", p -> ch);
             p = p -> nex;
         }
         puts ("");
    }

    return 0;
}