void unite (pnode &t,pnode l, pnode r) {
if (!l || !r) return void(t = l ? l : r);
if (l->prior < r->prior) swap (l, r);
pnode lt, rt;
split (r,lt, rt,l->val);
unite (l->l,l->l, lt);
unite (l->r,l->r, rt);
t=l;upd_sz(t);
}
void merge(pnode &t,pnode l,pnode r) //l->leftarray,r->rightarray,t->resulting array
{
lazy(l);
lazy(r);
if(!l || !r) t = l?l:r;
else if(l->prior>r->prior)merge(l->r,l->r,r),t=l;
else merge(r->l,l,r->l),t=r;
upd_sz(t);
operation(t);
}
void split(pnode t,pnode &l,pnode &r,int pos,int add=0)
{
if(!t)return void(l=r=NULL);
lazy(t);
int curr_pos = add + sz(t->l);
if(curr_pos<=pos)//element at pos goes to left subtree(l)
split(t->r,t->r,r,pos,curr_pos+1),l=t;
else
split(t->l,l,t->l,pos,add),r=t;
upd_sz(t);
operation(t);
}
void erase(pnode &t,int key){
if(!t)return;
else if(t->val==key){pnode temp=t;merge(t,t->l,t->r);free(temp);}
else erase(t->val<key?t->r:t->l,key);
upd_sz(t);
}
void insert(pnode &t,pnode it){
if(!t) t=it;
else if(it->prior>t->prior)split(t,it->l,it->r,it->val),t=it;
else insert(t->val<=it->val?t->r:t->l,it);
upd_sz(t);
}
