URAL 2040 Palindromes and Super Abilities 2

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 const int maxn = 5000010;
 4 struct PalindromicTree{
 5     struct node{
 6         int son[2],f,len;
 7         void init(int len){
 8             memset(son,0,sizeof son);
 9             this->len = len;
10         }
11     }e[maxn];
12     int tot,last,n;
13     char s[maxn];
14     int newnode(int len = 0){
15         e[tot].init(len);
16         return tot++;
17     }
18     int getFail(int x){
19         while(s[n - e[x].len - 1] != s[n]) x = e[x].f;
20         return x;
21     }
22     void init(){
23         last = tot = n = 0;
24         newnode(0);
25         newnode(-1);
26         e[0].f = 1;
27         s[n] = -1;
28     }
29     bool extend(int c){
30         s[++n] = c;
31         int cur = getFail(last);
32         bool isExtend = e[cur].son[c] == 0;
33         if(!e[cur].son[c]){
34             int newson = newnode(e[cur].len + 2);
35             e[newson].f = e[getFail(e[cur].f)].son[c];
36             e[cur].son[c] = newson;
37         }
38         last = e[cur].son[c];
39         return isExtend;
40     }
41 }pt;
42 char str[maxn];
43 int main(){
44     while(gets(str)){
45         pt.init();
46         for(int i = 0; str[i]; ++i){
47             if(pt.extend(str[i] - ‘a‘)) putchar(‘1‘);
48             else putchar(‘0‘);
49         }
50         putchar(‘\n‘);
51     }
52     return 0;
53 }