[HAOI2016]找相同字符(后缀自动机)

/*

一个建立后缀自动机一个跑就行
依旧是对于所有的祖先都有贡献
 

*/

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<queue>
#include<iostream>
#define ll long long 
#define mmp make_pair
#define M 400010
using namespace std;
int read()
{
	int nm = 0, f = 1;
	char c = getchar();
	for(; !isdigit(c); c = getchar()) if(c == '-') f = -1;
	for(; isdigit(c); c = getchar()) nm = nm * 10 + c - '0';
	return nm * f;
}
int len[M], fa[M], ch[M][26], sz[M], f[M], g[M], tim[M], a[M], cnt = 1, lst = 1;
char s[M]; 
ll ans = 0;

void insert(int c)
{
	int p = ++cnt, f = lst;
	lst = p;
	len[p] = len[f] + 1;
	sz[p] = 1;
	while(f && !ch[f][c]) ch[f][c] = p, f = fa[f];
	if(!f) fa[p] = 1;
	else
	{
		int q = ch[f][c];
		if(len[q] == len[f] + 1) fa[p] = q;
		else
		{
			int nq = ++cnt;
			memcpy(ch[nq], ch[q], sizeof(ch[q]));
			fa[nq] = fa[q];
			len[nq] = len[f] + 1;
			fa[q] = fa[p] = nq;
			while(f && ch[f][c] == q) ch[f][c] = nq, f = fa[f];
		}
	}
}
int main()
{
	scanf("%s", s + 1);
	int l = strlen(s + 1);
	for(int i = 1; i <= l; i++) insert(s[i] - 'a');
	for(int i = 1; i <= cnt; i++) tim[len[i]]++;
	for(int i = 1; i <= cnt; i++) tim[i] += tim[i - 1];
	for(int i = 1; i <= cnt; i++) a[tim[len[i]]--] = i;
	for(int i = cnt; i >= 1; i--) sz[fa[a[i]]] += sz[a[i]];
	scanf("%s", s + 1);
	l = strlen(s + 1);
	int now = 1, lt = 0;
	for(int i = 1; i <= l; i++)
	{
		int c = s[i] - 'a';
		if(ch[now][c]) lt++, now = ch[now][c];
		else {
			while(now && !ch[now][c]) now = fa[now];
			if(!now) now = 1, lt = 0;
			else lt = len[now] + 1, now = ch[now][c];
		}
		ans += 1ll * sz[now] * (lt - len[fa[now]]);
		g[now]++;
	}
	for(int i = cnt; i >= 1; i--)
	{
		ans += 1ll * sz[a[i]] * f[a[i]] * (len[a[i]] - len[fa[a[i]]]);
		f[fa[a[i]]] += f[a[i]] + g[a[i]];
	}
	cout << ans << "
";
	return 0;
}