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HDU 3948

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

const int MAXN = 100005 ;
const int N = 26 ;

struct Palindromic_Tree {
    int next[MAXN][N] ;
    int fail[MAXN] ;
    int cnt[MAXN] ;
    int num[MAXN] ;
    int len[MAXN] ;
    int S[MAXN] ;
    int last ;
    int n ;
    int p ;

    int newnode ( int l ) {
        for ( int i = 0 ; i < N ; ++ i ) next[p][i] = 0 ;
        cnt[p] = 0 ;
        num[p] = 0 ;
        len[p] = l ;
        return p ++ ;
    }

    void init () {
        p = 0 ;
        newnode (  0 ) ;
        newnode ( -1 ) ;
        last = 0 ;
        n = 0 ;
        S[n] = -1 ;
        fail[0] = 1 ;
    }

    int get_fail ( int x ) {
        while ( S[n - len[x] - 1] != S[n] ) x = fail[x] ;
        return x ;
    }

    void add ( int c ) {
        c -= 'a' ;
        S[++ n] = c ;
        int cur = get_fail ( last ) ;
        if ( !next[cur][c] ) {
            int now = newnode ( len[cur] + 2 ) ;
            fail[now] = next[get_fail ( fail[cur] )][c] ;
            next[cur][c] = now ;
            num[now] = num[fail[now]] + 1 ;
        }
        last = next[cur][c] ;
        cnt[last] ++ ;
    }

    void count () {
        for ( int i = p - 1 ; i >= 0 ; -- i ) cnt[fail[i]] += cnt[i] ;
        
    }
} str;

int main()
{
    int t;
    string a;
    cin>>t;
    int k=1;
    while(t--)
    {
        cin>>a;
        str.init();
        int len=a.size();
        for(int i=0;i<len;i++)
        {
            str.add(a[i]);
        }
        cout<<"Case #"<<k++<<": ";
        cout<<str.p-2<<endl;
    }
    return 0;
 } 

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原文：https://www.cnblogs.com/tianming1/p/11609871.html