BZOJ1500 maintenance series treap implementation

A long time ago, I heard that treap could write this question, and then watched the god code, and then ~ It is much easier to write than using splay.

Here we need to change the method of treap. A normal treap maintains a weight value for each node and rotates it based on the weight value. In this way, we can divide a treap into two trees, the method is to create a useless node and then give the node an extremely powerful value. In this way, the node is the root node, and the left and right sub-villages of the node divide the original tree into two trees, in this way, we can easily extract a range and maintain it like splay.

Then ~ Actually ~ I used not the rotation method to extract the interval, but split and merge to split a tree into two and merge the two into one. For specific implementation, see the code below.

At first, this question was always TLE. Later I found it was because I used the system's rand function ~ Write a random number generator ~ Then pass through ~ But it is still slower than splay.

SPOJ1470 I haven't tried yet ~ But I think the visual test should drop TLE ~ After all, splay with poor SPOJ connection optimization will crash. Alas

#define INF 2000000000#define N 500010struct Node;Node *null,*root;struct Node{    int w,sz,val,sum,ls,rs,ss,lzy1,lzy2;    Node *lft,*rht;    void split(int,Node*&,Node*&);    void same(int v)    {        if(this==null) return;        lzy2=val=v;        sum=v*sz;        ls=rs=ss=max(sum,v);    }    void rev()    {        if(this==null) return;        lzy1^=1;        swap(lft,rht);        swap(ls,rs);    }    Node *pushup()    {        sz=lft->sz+1+rht->sz;        sum=lft->sum+val+rht->sum;           ls=max(lft->ls,lft->sum+val+max(0,rht->ls));        rs=max(rht->rs,rht->sum+val+max(0,lft->rs));           ss=max(0,lft->rs)+val+max(0,rht->ls);        ss=max(ss,max(lft->ss,rht->ss));           return this;    }    Node *pushdown()    {        if(lzy1)        {            lft->rev();            rht->rev();            lzy1=0;        }        if(lzy2!=-INF)        {            lft->same(lzy2);            rht->same(lzy2);            lzy2=-INF;        }        return this;    }};Node *merge(Node *p,Node *q){    if(p==null) return q;    if(q==null) return p;    if(p->w<q->w)    {        p->pushdown();        p->rht=merge(p->rht,q);        return p->pushup();    }    q->pushdown();    q->lft=merge(p,q->lft);    return q->pushup();}void Node::split(int need,Node *&p,Node *&q){    if(this==null)    {        p=q=null;        return;    }    pushdown();    if(lft->sz>=need)    {        lft->split(need,p,q);        lft=null;        pushup();        q=merge(q,this);        return;    }    rht->split(need-(lft->sz+1),p,q);    rht=null;    pushup();    p=merge(this,p);    return;}Node data[N],*pool[N];int top,cnt;Node* newnode(int c){    Node *x;    if(top) x=pool[top--];    else x=&data[cnt++];    x->lft=x->rht=null;    x->sz=1; x->lzy1=0; x->lzy2=-INF;    x->val=x->sum=x->ls=x->rs=x->ss=c;    x->w=rands();    return x;}void init(){    cnt=1; top=0;    null=&data[0];    null->sz=null->sum=0;    null->val=null->ls=null->rs=null->ss=-INF;    null->lzy1=0;    null->lzy2=-INF;    null->lft=null->rht=null;}//---------------------------------------------------------void erase(Node *rt){    if(rt==null) return;    erase(rt->lft);    erase(rt->rht);    pool[++top]=rt;}int n,m;char ord[20];int a,b,c;int main (){init();        root=null;        n=fastget();        m=fastget();        for(int i=0;i<n;i++)        {            a=fastget();            root=merge(root,newnode(a));        }        while (m--)        {            scanf("%s",ord);            Node *p,*q,*r,*s;            if(ord[0]=='I')            {                a=fastget();                n=fastget();                root->split(a,p,q);                for(int i=0;i<n;i++)                {                    b=fastget();                    p=merge(p,newnode(b));                }                root=merge(p,q);            }else if(ord[0]=='D')            {                a=fastget();                b=fastget();                b=a+b-1;                root->split(a-1,p,q);                q->split(b-a+1,r,s);                erase(r);                root=merge(p,s);            }else if(ord[0]=='M' && ord[2]=='K')            {                a=fastget();                b=fastget();                c=fastget();                b=b+a-1;                root->split(a-1,p,q);                q->split(b-a+1,r,s);                r->same(c);                root=merge(p,merge(r,s));            }else if(ord[0]=='R')            {                a=fastget();                b=fastget();                b=b+a-1;                root->split(a-1,p,q);                q->split(b-a+1,r,s);                r->rev();                root=merge(p,merge(r,s));            }else if(ord[0]=='G')            {                a=fastget();                b=fastget();                b=a+b-1;                root->split(a-1,p,q);                q->split(b-a+1,r,s);                fastput(r->sum);                root=merge(p,merge(r,s));            }            else if(ord[0]=='M') fastput(root->ss);        }          return 0;}