BZOJ1507 [NOI2003]Editor

是一道裸的Splay（反正我不会Splay，快嘲笑我！）

只需要维护在数列上加点删点操作即可，不会写Splay的渣渣只好Orz iwtwiioi大神一下了。（后来发现程序直接抄来了。。。）

就当我的第一个Splay程序吧。

 /**************************************************************
     Problem: 1507
     User: rausen
     Language: C++
     Result: Accepted
     Time:2560 ms
     Memory:43860 kb
 ****************************************************************/

 #include <cstdio>
 #include <cstring>

 using namespace std;
 char strI[];

 struct Splay{
     struct node{
         node *son[], *fa;
         char key;
         int size;
         node(){
             son[] = son[] = fa = NULL;
             size = key = ;
         }
         void pushup(){
             size = son[] -> size + son[] -> size + ;
         }

         bool d(){
             return this == fa -> son[];
         }

         void setc(node *c, int d){
             son[d] = c;
             c -> fa = this;
         }
     } * null, *root;

     Splay(){
         null = new node;
         root = null;
         root = newnode();
         node *t = newnode();
         root -> setc(t, );
         root -> pushup();
     }

     node *newnode(char K){
         node *res = new node;
         res -> son[] = res -> son[] = res -> fa = null;
         res -> key  = K, res -> size = ;
         return res;
     }

     void rotate(node *r){
         node *fa = r -> fa;
         bool d = r -> d();
         fa -> fa -> setc(r, fa -> d());
         fa -> setc(r -> son[!d], d);
         r -> setc(fa, !d);
         fa -> pushup();
         if (fa == root) root = r;
     }

     void splay(node *r, node *X){
         while (r -> fa != X){
             if (r -> fa -> fa == X) rotate(r);
             else r -> d() == r -> fa -> d() ? (rotate(r -> fa), rotate(r)) : (rotate(r), rotate(r));
         }
         r -> pushup();
     }

     node *sel(int k){
         int s;
         for(node *t = root; ;){
             s = t -> son[] -> size;
             if (s == k) return t;
             t = t -> son[k > s];
             if (k > s) k -= s + ;
         }
     }

     node *getrange(int l, int r){
         node *left = sel(l); splay(left, null);
         node *right = sel(r); splay(right, left);
         return right;
     }

     void insert(int w, int cur){
         node *t = getrange(w, w + );
         t -> setc(build(, cur), );
         t -> pushup();
         splay(t, null);
     }

     void remove(int w, int n){
         node *t = getrange(w, w + n + );
         t -> setc(null, );
         t -> pushup();
         splay(t, null);
     }

     node *build(int l, int r){
         if (l >= r) return null;
         int m = (l + r) >> ;
         node *t = newnode(strI[m]);
         t -> setc(build(l, m), );
         t -> setc(build(m + , r), );
         t -> pushup();
         return t;
     }

     void print(node *r){
         if (r == null) return;
         print(r -> son[]);
         printf("%c", r -> key);
         print(r -> son[]);
     }

     void print(int w, int n){
         node *t = getrange(w, w + n + );
         print(t -> son[]);
         printf("\n");
     }
 } splay;

 char s[];

 int main(){
     int n, T, cur, w = ;
     scanf("%d", &T);
     while (T--){
         scanf("%s", s);
         if (s[] == 'M')
             scanf("%d", &w);
         else if (s[] == 'P')
             --w;
         else if (s[] == 'N')
             ++w;
         else if (s[] == 'D'){
             scanf("%d", &n);
             splay.remove(w, n);
         } else
         if (s[] == 'G'){
             scanf("%d", &n);
             splay.print(w, n);
         } else
         if (s[] = 'I'){
             scanf("%d", &n);
             cur = ;
             while (n--){
                 while(strI[cur] = getchar(), strI[cur] == '\n');
                 cur++;
             }
             splay.insert(w, cur);
         }
     }
     return ;
 }