【后缀回文自动机】 URAL 1960 Palindromes and Super Abilities

后缀回文自动机的学习链接：链接

因为自动机上每一个节点代表目前的串的一个回文串，所以只要统计当前自动机总共有o多少个节点就可以了。。

#include <iostream>
#include <queue> 
#include <stack> 
#include <map> 
#include <set> 
#include <bitset> 
#include <cstdio> 
#include <algorithm> 
#include <cstring> 
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 100005
#define maxm 2000005
#define eps 1e-10
#define mod 1000000007
#define INF 0x3f3f3f3f
#define PI (acos(-1.0))
#define lowbit(x) (x&(-x))
#define mp make_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid 
#define rson o<<1 | 1, mid+1, R
#define pii pair<int, int>
//#pragma comment(linker, "/STACK:16777216")
typedef long long LL;
typedef unsigned long long ULL;
//typedef int LL;
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
// head

struct node
{
	int len;
	node *ch[26], *link;
}pool[maxn], *tot, *last;
char s[maxn];
int n;

void init(void)
{
	memset(pool, 0, sizeof pool);
	tot = &pool[2];
	last = &pool[1];
	pool[0].len = -1;
	pool[1].link = &pool[0];
}

bool add(void)
{
	char c = s[n-1];
	node *p = last;
	while(p && c != s[n - p->len - 2]) p = p->link;
	bool res = false;
	if(!p->ch[c]) {
		res = true;
		node *q = last = tot++;
		q->len = p->len + 2;
		p->ch[c] = q;
		do p = p->link; while(p && c != s[n - p->len - 2]);
		if(!p) q->link = &pool[1];
		else q->link = p->ch[c];
	}
	else last = p->ch[c];
	return res;
}

void work(void)
{
	int ans = 0;
	char c;
	n = 0;
	s[n++] = '#';
	while((c = getchar()) != '\n') {
		c -= 'a';
		s[n++] = c;
		ans += add();
		printf("%d ", ans);
	}
}

int main(void)
{
	init();
	work();

	return 0;
}