manacher算法模板

char s[maxn << 1];
int p[maxn << 1];
int Len[maxn];

void manacher(){
	int len = strlen(s), id = 0, maxlen=0;
	for(int i = len; i >= 0; --i){
		s[i + i + 2] = s[i];
		s[i + i + 1] = '#';
	}
	s[0] = '*';
	for(int i = 2; i < 2 * len + 1; ++i){
		if(p[id] + id > i) p[i] = min(p[2 * id - i], p[id] + id - i);
		else p[i] = 1;
		while(s[i - p[i]] == s[i + p[i]]) ++p[i];
		if(id + p[id] < i+p[i])  id = i;
                if(i % 2 == 0) Len[i / 2 - 1] = p[i] - 1;
	}
}