【模板】文艺平衡树（Splay）

[[Luogu3391]【模板】文艺平衡树（Splay）]

非指针版

#define lo ch[o][0]
#define ro ch[o][1]
void maintain(int o){sz[o]=1+sz[lo]+sz[ro];}
void pushdown(int o){if(!laz[o]) return ; swap(lo, ro); if(lo) laz[lo]^=1; if(ro) laz[ro]^=1; laz[o]=0;}
void ins(int &o, int x){
    if(!o){o=++cnt; val[o]=x; sz[o]=1; return ;}
    if(x < val[o]) ins(ch[o][0], x); else ins(ch[o][1], x); maintain(o);
}
void rot(int &o, int d){
    pushdown(o); int p=ch[o][d^1]; pushdown(p);
    ch[o][d^1]=ch[p][d]; ch[p][d]=o; maintain(o); maintain(p); o=p; 
}
int scmp(int o, int &k){if(sz[lo]+1 == k) return -1; if(sz[lo]+1 > k) return 0; k-=sz[lo]+1; return 1;}
void splay(int &o, int k){
    if(!o) return ; pushdown(o); int d=scmp(o, k); if(d == -1) return ;
    int p=ch[o][d]; if(!p) return ; pushdown(p);
    int k2=k, d2=scmp(p, k2); if(d2 == -1) {rot(o, d^1); return ;}
    splay(ch[p][d2], k2); if(d == d2) rot(o, d^1); else rot(ch[o][d], d); rot(o, d^1);
}
void rev(int l, int r){
    splay(rt, r+2); splay(ch[rt][0], l);
    if(ch[ch[rt][0]][1]) laz[ch[ch[rt][0]][1]]^=1;
}

void print(int o){
    pushdown(o);
    if(ch[o][0]) print(ch[o][0]);
    if(val[o] != n+1 && val[o]) printf("%d ", val[o]);
    if(ch[o][1]) print(ch[o][1]);
}

void solve(){
    n=read(), m=read();
    for(int i=0; i <= n+1; i++) ins(rt, i), splay(rt, i+1); 
    for(int i=1; i <= m; i++){int l=read(), r=read(); rev(l, r);}
    print(rt);
}

指针版（以前不压行的代码看着好长好啰嗦啊）

struct node
{
    node* ch[2];
    int laz,s,v;
    node(int v):v(v){s=1;ch[0]=ch[1]=NULL;laz=0;}
    int cmp(int &k)
    {
        int ss=(ch[0] == NULL ? 0 : ch[0]->s);
        if(k == ss+1) return -1;
        if(k > ss) {k-=ss+1;return 1;}
        return 0;
    }
    void maintain(){ 
        s=1; 
        if(ch[0]!=NULL) s+=ch[0]->s; 
        if(ch[1]!=NULL) s+=ch[1]->s; 
    }
    void pushdown()
    {
        if(laz)
        {
            swap(ch[0],ch[1]);
            if(ch[0]!=NULL) ch[0]->laz^=1;
            if(ch[1]!=NULL) ch[1]->laz^=1;
            laz=0;
        }
    }
};
node* rt=NULL;

void rot(node* &o,int d)
{
    o->pushdown();node* k=o->ch[d^1];
    k->pushdown();o->ch[d^1]=k->ch[d];k->ch[d]=o;
    o->maintain();k->maintain();o=k;
}

void splay(node* &o,int k)
{
    if(o == NULL) return ;
    o->pushdown();
    int d=o->cmp(k);
    if(d != -1)
    {

        node* p=o->ch[d];if(p == NULL) return ; 
        p->pushdown();
        int k2=k,d2=p->cmp(k2);
        if(d2 != -1) 
        { 
            splay(p->ch[d2],k2); 
            if(d == d2) rot(o,d^1); 
            else rot(o->ch[d],d); 
        }
        rot(o,d^1);
    }
}

void ins(node* &o,int x)
{
    if(o == NULL){o=new node(x);return ;}
    int d=(x < o->v ? 0 : 1);ins(o->ch[d],x);
    o->maintain();
}

void rev(int l,int r)
{
    splay(rt,r+2);
    splay(rt->ch[0],l);
    if(rt->ch[0]->ch[1] != NULL) 
    rt->ch[0]->ch[1]->laz^=1;
}

void print(node* o)
{
    if(o==NULL) return ;
    o->pushdown();
    print(o->ch[0]);
    if(o->v != n+1 && o->v)printf("%d ",o->v);
    print(o->ch[1]);
}
void solve(){
    n=read();m=read();
    for(int i=1;i<=n+2;i++) {ins(rt,i-1);splay(rt,i);}
    while(m--){int l=read(),r=read(); rev(l,r);}
    print(rt);
}