最早的板子，学自Ez大佬：

1 #include
      
         2 #include
       
          3 using namespace std;  4    5 class Splay{  6 public:  7     Splay(){  8         root=NULL;  9         for(top;top
        
         cnt,update(root); 15         else    if(root==NULL) 16             root=newnode(val,NULL); 17         else    splay(insert(root,val),NULL); 18     } 19     inline void erase(int val){ 20         if(find(val)!=NULL) erase(root,1); 21     } 22     inline int rnk(int val){ 23         if(find(val)!=NULL) return size(root->son[0])+1; 24         else    return 0; 25     } 26     inline int qry(int kth){ 27         if(size(root)
         
          size(t->son[0])){ 30                 kth-=size(t->son[0]); 31                 if(kth<=t->cnt) 32                     return t->v; 33                 else    kth-=t->cnt,t=t->son[1]; 34             } 35             else    t=t->son[0]; 36         } 37     } 38     inline int prv(int val){ 39         int ret=-0x7fffffff; 40         for(node *t=root;t;){ 41             if(t->v
          
           v) 43                     ret=t->v; 44             } 45             t=t->son[val>t->v]; 46         } 47         return ret; 48     } 49     inline int nxt(int val){ 50         int ret=0x7fffffff; 51         for(node *t=root;t;){ 52             if(t->v>val){ 53                 if(ret>t->v) 54                     ret=t->v; 55             } 56             t=t->son[val>=t->v]; 57         } 58         return ret; 59     } 60 private: 61     struct node{ 62         int v,cnt,siz; 63         node *son[2],*f; 64         node(){son[0]=son[1]=f=NULL;v=cnt=siz=0;} 65     }*root; 66     const static int siez=100100; 67     node *stk[siez],tree[siez];int top; 68     inline node * newnode(int v,node *f){ 69         node *t=stk[--top]; 70         t->siz=t->cnt=1;t->v=v; 71         t->son[1]=t->son[0]=NULL; 72         t->f=f; 73         return t; 74     } 75     inline void freenode(node *t){ 76         stk[top++]=t; 77     } 78     inline int size(node* t){ 79         return t==NULL?0:t->siz; 80     } 81     inline void update(node *t){ 82         if(t!=NULL) 83             t->siz=t->cnt+size(t->son[0])+size(t->son[1]); 84     } 85      86     inline bool son(node* f,node* s){ 87         if(f==NULL) return 0; 88         return f->son[1]==s; 89     } 90     inline void connect(node *f,node *s,bool k){ 91         if(f!=NULL) f->son[k]=s; 92         else    root=s; 93         if(s!=NULL) s->f=f; 94     } 95     inline void rotate(node* t){ 96         node *f=t->f,*g=f->f; 97         bool a=son(f,t),b=!a; 98         connect(f,t->son[b],a); 99         connect(g,t,son(g,f));100         connect(t,f,b);101         update(f);102         update(t);103     }104     inline  void splay(node *t,node *p){105         if(t){106             while(t->f!=p){107                 node *f =t->f,*g=f->f;108                 if(g==p)    rotate(t);109                 else{110                     if(son(g,f)^son(f,t))111                         rotate(t),rotate(t);112                     else113                         rotate(f),rotate(t);114                 }115             }116         }117     }118     inline node *find(int val){119         node *t=root;120         while(t!=NULL &&t->v!=val){121             t=t->son[val>=t->v];122         }123         return splay(t,NULL ),t;124     }125     node *insert(node *t,int val){126         node *ret=t->son[val>=t->v];127         if(ret==NULL)128             ret=t->son[val>=t->v]=newnode(val,t);129         else ret=insert(ret,val);130         return update(t),ret;131     }132     inline void erase(node *t){133         if(t->son[0]==NULL)134             connect(NULL ,t->son[1],0),update(root);135         else    if(t->son[1]==NULL){136             connect(NULL,t->son[0],1),update(root);137         }138         else{139             node *p=t->son[0];140             while(p->son[1]!=NULL)  p=p->son[1];141             splay(p,t);142             connect(NULL,p,0);143             connect(p,t->son[1],1);144             update(root);145         }146         freenode(t);147     }148     inline void erase(node *t ,int k){149         t->cnt-=k;150         if(t->cnt<=0)   erase(t);151         else    update(t);152     }153 }s;154 int main(){155     freopen("phs.in","r",stdin);156     freopen("phs.out","w",stdout);157     int n,op,x;158     scanf("%d",&n);159     while(n--){160         scanf("%d%d",&op,&x);161         switch(op){162             case 1: s.insert(x);163             break;164             case 2 :s.erase(x);165             break;166             case 3: printf("%d\n",s.rnk(x));167             break;168             case 4:printf("%d\n",s.qry(x));169             break;170             case 5:printf("%d\n",s.prv(x));171             break;172             default:printf("%d\n",s.nxt(x));173             break;174         }175     }176 }
          
         
        
       
      

自己修改的板子（其实没变化）：

1 #define Troy  2   3 #include "bits/stdc++.h"  4   5 #define inf 0x7fffffff  6   7 using namespace std;  8   9 inline int read(){ 10     int s=0,k=1;char ch=getchar(); 11     while(ch<'0'|ch>'9')    ch=='-'?k=-1:0,ch=getchar(); 12     while(ch>47&ch<='9')    s=s*10+(ch^48),ch=getchar(); 13     return s*k; 14 } 15  16 const int N=2e5+5; 17  18 #define size(t) (t?t->size:0) 19 #define son(f,s)    (f?f->son[1]==s:0) 20 #define update(t)    (t?t->size=t->cnt+size(t->son[0])+size(t->son[1]):0) 21  22 class Splay{ 23 public: 24     Splay(){
   for(root=NULL;top
     
      cnt,update(root); 28         else    if(root)    splay(insert(root,val),NULL); 29         else    root=newnode(val,NULL); 30     } 31  32     inline void erase(int val){
   if(find(val))   erase(root,1);} 33  34     inline int rnk(int val){ 35         if(find(val))   return size(root->son[0])+1; 36         else    return 0; 37     } 38  39     inline int qry(int kth){ 40         if(size(root)
      
       size(t->son[0])){ 43                 kth-=size(t->son[0])+t->cnt; 44                 if(kth<=0)  return t->val; 45                 else    t=t->son[1]; 46             }else t=t->son[0]; 47     }    48  49     inline int prv(int val){ 50         int ret=-inf; 51         for(node *t=root;t;t=t->son[val>t->val]) 52             if(t->val
       
        
         val)  ret=t->val; 53         return ret;   54     } 55  56     inline int nxt(int val){ 57         int ret=inf; 58         for(node *t=root;t;t=t->son[val>=t->val]) 59             if(t->val>val&&ret>t->val)  ret=t->val; 60         return ret; 61     } 62 private: 63     struct node{ 64         node *f,*son[2]; 65         int val,cnt,size; 66     }tree[N],*root,*stk[N];int top; 67  68     inline node* newnode(int val,node *f){ 69         node *t=stk[--top];*t=(node){f,NULL,NULL,val,1,1}; 70         return t; 71     } 72  73     inline void freenode(node *t){stk[top++]=t;} 74  75     inline void connect(node *f,node *s,int k){ 76         if(f)   f->son[k]=s;else root=s; 77         if(s)   s->f=f; 78     } 79  80     inline void rotate(node *t){ 81         node *f=t->f,*g=f->f;int a=son(f,t),b=!a; 82         connect(f,t->son[b],a); 83         connect(g,t,son(g,f)); 84         connect(t,f,b); 85         update(f),update(t); 86     } 87  88     inline void splay(node *t,node *p){ 89         if(t)for(;t->f!=p;rotate(t)) 90             if(t->f->f!=p)  rotate(son(t->f,t)==son(t->f->f,t->f)?t->f:t); 91     } 92  93     inline node *find(int val){ 94         node *t=root; 95         for(;t&&t->val!=val;t=t->son[val>=t->val]); 96         return splay(t,NULL),t; 97     } 98  99     inline node *insert(node *t,int val){100         node *ret=t->son[val>=t->val];101         if(ret) ret=insert(ret,val);else    ret=t->son[val>=t->val]=newnode(val,t);102         return update(t),ret;103     }104 105     inline void erase(node *t){106         if(t->son[0]==NULL) connect(NULL,t->son[1],0);107         else    if(t->son[1]==NULL) connect(NULL,t->son[0],0);108         else    {node *p=t->son[0];109             while(p->son[1])    p=p->son[1];110             splay(p,t);111             connect(NULL,p,0),connect(p,t->son[1],1);112         }update(root),freenode(t);113     }114 115     inline void erase(node *t,int k){116         t->cnt-=k;117         if(t->cnt<=0)   erase(t);else   update(t);118     }119 }s;120 int main(){121     freopen("phs.in","r",stdin);122     freopen("phs.out","w",stdout);123     int n,op,x;124     n=read();125     while(n--){126         op=read(),x=read();127         switch(op){128             case 1: s.insert(x);129             break;130             case 2 :s.erase(x);131             break;132             case 3:printf("%d\n",s.rnk(x));133             break;134             case 4:printf("%d\n",s.qry(x));135             break;136             case 5:printf("%d\n",s.prv(x));137             break;138             default:printf("%d\n",s.nxt(x));139             break;140         }141     }142 }