hihocoder 1445 : 后缀自动机二·重复旋律5（后缀自动机）

给入门新手的模板题，套kuangbin大佬的模板。
当前节点的minlen就等于当前节点的fa节点的maxlen+1。

#include <bits/stdc++.h>
using namespace std;
const int CHAR = 26;
const int MAXN = 1100010;
long long res = 0;
struct SAM_Node
{
    SAM_Node *fa,*next[CHAR];
    int len;
    int id,pos;
    SAM_Node() {}
    SAM_Node(int _len)
    {
        fa = 0;
        len = _len;
        memset(next,0,sizeof(next));
    }
};
SAM_Node SAM_node[MAXN*2], *SAM_root, *SAM_last;
int SAM_size;
SAM_Node *newSAM_Node(int len)
{
    SAM_node[SAM_size] = SAM_Node(len);
    SAM_node[SAM_size].id = SAM_size;
    return &SAM_node[SAM_size++];
}
SAM_Node *newSAM_Node(SAM_Node *p)
{
    SAM_node[SAM_size] = *p;
    SAM_node[SAM_size].id = SAM_size;
    return &SAM_node[SAM_size++];
}
void SAM_init()
{
    SAM_size = 0;
    SAM_root = SAM_last = newSAM_Node(0);
    SAM_node[0].pos = 0;
}
void SAM_add(int x,int len)
{
    SAM_Node *p = SAM_last, *np = newSAM_Node(p->len+1);
    np->pos = len;
    SAM_last = np;
    for(; p && !p->next[x]; p = p->fa)
        p->next[x] = np;
    if(!p)
    {
        np->fa = SAM_root;
        res += (np->len-np->fa->len);
        return;
    }
    SAM_Node *q = p->next[x];
    if(q->len == p->len + 1)
    {
        np->fa = q;
        res += (np->len-np->fa->len);
        return;
    }
    SAM_Node *nq = newSAM_Node(q);
    nq->len = p->len + 1;
    q->fa = nq;
    np->fa = nq;
    for(; p && p->next[x] == q; p = p->fa)
        p->next[x] = nq;
    res += (np->len-np->fa->len);
}
void SAM_build(char *s)
{
    SAM_init();
    int len = strlen(s);
    for(int i = 0; i < len; i++)
        SAM_add(s[i] - 'a',i+1);
}

char str[MAXN];

int main()
{
    scanf("%s",str);
    SAM_build(str);
    printf("%lld\n",res);
    return 0;
}