sam模板

SAM模板

struct SAM{
    static const int maxn =   * ;
    struct node{
        node*nxt[],*fail;
        int len;
    };

    node*root;int cnt;
    node no[maxn];
    node*newnode(){
        return &no[cnt++];
    }
    SAM(){
        cnt = ;
        root = newnode();
    }

    node* add(node*p,int c){
        node*cur = newnode();
        cur->len = p->len+;
        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+){
            cur->fail = q;
        }else{
            node*nq = newnode();
            *nq = *q;
            nq->len = p->len+;
            q->fail = cur->fail = nq;
            while(p&&p->nxt[c]==q)p->nxt[c] = nq,p = p->fail;
        }
        return cur;
    }

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