sam模板

SAM模板 

struct SAM{
    static const int maxn =  300010 * 2;
    struct node{
        node*nxt[26],*fail;
        int len;
    };
    
    node*root;int cnt;
    node no[maxn];
    node*newnode(){
        return &no[cnt++];
    }
    SAM(){
        cnt = 0;
        root = newnode();
    }
    
    node* add(node*p,int c){
        node*cur = newnode();
        cur->len = p->len+1;
        while(p &&!p->nxt[c])p->nxt[c] = cur,p = p->fail;
        if(!p){
            cur->fail = root;return cur;
        }
        node*q = p->nxt[c];
        if(q->len == p->len+1){
            cur->fail = q;
        }else{
            node*nq = newnode();
            *nq = *q;
            nq->len = p->len+1;
            q->fail = cur->fail = nq;
            while(p&&p->nxt[c]==q)p->nxt[c] = nq,p = p->fail;
        }
        return cur;
    }

    ll getNumOfDistinctSubstrings(){
        auto ans = 0;
        REP(i,1,cnt)ans+=no[i].len-no[i].fail->len;
        return (ans);
    }
};