最早的板子，学自Ez大佬：
1 #include<cstdio> 2 #include<cstdlib> 3 using namespace std; 4 5 class Splay{ 6 public: 7 Splay(){ 8 root=NULL; 9 for(top;top<siez;top++) 10 stk[top]=tree+top; 11 } 12 inline void insert(int val){ 13 if(find(val)!=NULL) 14 ++root->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)<kth) return 0; 28 for(node *t=root;t;){ 29 if(kth>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<val){ 42 if(ret<t->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 else 113 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 ",s.rnk(x)); 167 break; 168 case 4:printf("%d ",s.qry(x)); 169 break; 170 case 5:printf("%d ",s.prv(x)); 171 break; 172 default:printf("%d ",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<N;++top) stk[top]=tree+top;} 25 26 inline void insert(int val){ 27 if(find(val)) ++root->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)<kth) return 0; 41 for(node *t=root;t;) 42 if(kth>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) 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 ",s.rnk(x)); 133 break; 134 case 4:printf("%d ",s.qry(x)); 135 break; 136 case 5:printf("%d ",s.prv(x)); 137 break; 138 default:printf("%d ",s.nxt(x)); 139 break; 140 } 141 } 142 }