Hdu3487-Play with Chain(伸展树分裂合并)

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
using namespace std;
const int INF=1e9+7;
const int maxn=300005;
int N,M,ans,A[maxn],cnt;  //A数组保存数，cnt是节点标号，我是用数组模拟的
struct treap
{
    treap* son[2];  //左右儿子
    int v,s,rev;
    treap(){ v=s=rev=0; son[0]=son[1]=NULL; }
    treap(int nv);
    int rk(){ return son[0]->s+1; }  //排名，第几个数
    int cmp(int k)  //比较，如果相等返回-1，小于返回0，大于1
    {
        if(k==rk()) return -1;
        return k<rk()?0:1;
    }
    void pushup(){ s=son[0]->s+son[1]->s+1; }  //更新大小
    void pushdown();  //处理懒惰标记
}null,tr[maxn];
treap::treap(int nv)
{
    v=nv;
    s=1;
    rev=0;
    son[0]=son[1]=&null;
}
void treap::pushdown()
{
    if(this==&null) return;
    if(rev)
    {
        swap(son[0],son[1]);
        son[0]->rev^=1;
        son[1]->rev^=1;
        rev=0;
    }
}
treap* NewNode(int x)
{
    tr[cnt]=treap(x);
    return tr+cnt++;
}
struct splaytree
{
    int Size;
    treap* root;
    splaytree(){ Size=0; root=&null; }
    void Rotate(treap* &t,int d)  //翻转操作
    {
        t->pushdown();
        treap* p=t->son[d^1];
        p->pushdown();
        t->son[d^1]=p->son[d];
        p->son[d]=t;
        t->pushup();
        t=p;
        t->pushup();
    }
    void Splay(treap* &t,int k)  //将第k大的节点伸展到根
    {
        t->pushdown();
        int d=t->cmp(k);
        if(d!=-1)
        {
            if(d) Splay(t->son[d],k- t->rk());
            else Splay(t->son[d],k);
            Rotate(t,d^1);
        }
        t->pushup();
    }
    void Build(treap* &t,int le,int ri)  //将N个数建成一棵树
    {
        if(le>ri) return;
        int mid=(le+ri)/2;
        t=NewNode(mid);
        Build(t->son[0],le,mid-1);
        Build(t->son[1],mid+1,ri);
        t->pushup();
    }
    void Cut(treap* &t,int a,int b,int c)
    {
        int len=b-a+1;
        if(len==N) return; //是整个区间就不用管了
        Splay(t,a); t->pushdown();  //分裂出左边的
        treap *L=t->son[0];
        L->pushdown();
        t->son[0]=&null; t->pushup();

        Splay(t,len); t->pushdown(); //分裂出右边的
        treap *R=t->son[1];
        R->pushdown();
        t->son[1]=&null; t->pushup();

        treap *nt;
        if(R!=&null) //左右合并
        {
            nt=R;
            Splay(nt,1);
            nt->son[0]=L; nt->pushup();
        }
        else
        {
            nt=L;
            Splay(nt,a-1);
            nt->son[1]=R; nt->pushup();
        }
        if(c+len==N) //在整个之后特殊处理一下就好
        {
            Splay(nt,c);
            Splay(t,1);
            t->son[0]=nt;
            t->pushup();
            return;
        }
        Splay(nt,c+1);
        treap *l=nt->son[0]; l->pushdown();
        nt->son[0]=&null; nt->pushup();
        t->son[1]=nt; t->pushup();
        Splay(t,1);
        t->son[0]=l; t->pushup();
    }
    void Reverse(treap* &t,int a,int b) //翻转
    {
        Splay(t,a); //左边
        treap *L=t->son[0];
        L->pushdown();
        t->son[0]=&null; t->pushup();
        Splay(t,b-a+1);  //右边
        treap *R=t->son[1];
        R->pushdown();
        t->son[1]=&null; t->pushup();
        t->rev^=1; //置翻转标记
        t->pushdown();
        t->son[0]=L; t->pushup();
        Splay(t,b);
        t->son[1]=R; t->pushup();
    }
    void PushAll(treap* &t) //中序遍历
    {
        if(t==&null) return;
        t->pushdown();
        PushAll(t->son[0]);
        A[++ans]=t->v;
        PushAll(t->son[1]);
        t->pushup();
    }
};
int main()
{
    while(scanf("%d%d",&N,&M)!=EOF)
    {
        if(N<0&&M<0) break;
        splaytree spt; cnt=0;
        spt.Build(spt.root,1,N); //建树
        int a,b,c;
        char op[10];
        while(M--)
        {
            scanf("%s",op);
            if(op[0]==‘C‘) //CUT操作
            {
                scanf("%d%d%d",&a,&b,&c);
                spt.Cut(spt.root,a,b,c);
            }
            else  //FLIP操作
            {
                scanf("%d%d",&a,&b);
                spt.Reverse(spt.root,a,b);
            }

        }
        ans=0;
        spt.PushAll(spt.root); //整个下压
        for(int i=1;i<=ans;i++)
            printf("%d%c",A[i],i==ans?‘\n‘:‘ ‘);
    }
    return 0;
}