BZOJ 1507 NOI 2003 Editor Splay

来源：互联网发布：linux所有版本编辑：程序博客网时间：2024/06/05 14:50

题目大意：维护一种数据结构，它可以：

1.移动光标

2.在光标之后插入一段字符串

3.删除光标之后的n个字符

4.输出光标之后的n个字符

5.移动光标

思路：Splay，没什么特别的。但是有几个需要注意的地方。1.题中说：delete操作不会越界。但是其实有可能会越界，比如样例就越界了。。

2.输出的时候一定不要偷懒。我刚开始写的时候就把输出写成nlogn输出的了，然后果断T了吗，我还以为是哪里死循环了，结果是这里被卡了！以后再也不偷懒随便加logn了。。。

CODE：

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#define MAX (1 << 22|100)using namespace std;struct Complex{    char c;    int size;    Complex *son[2],*father;    void Combine(Complex *a,bool dir) {        son[dir] = a;        a->father = this;    }      bool Check() {    return father->son[1] == this;    }    void PushUp() {    size = son[0]->size + son[1]->size + 1;    }}*nil = new Complex(),*root;void Pretreatment();Complex *BuildTree(int l,int r);Complex *Kth(Complex *a,int k);Complex *NewComplex(char val);inline void Rotate(Complex *a,bool dir);inline void Splay(Complex *a,Complex *aim);void Print(Complex *a);char src[MAX];int asks,now;char s[MAX];int main(){    Pretreatment();    cin >> asks;    for(int x,i = 1;i <= asks; ++i) {    scanf("%s",s);    if(s[0] == 'M')scanf("%d",&now);    else if(s[0] == 'I') {    scanf("%d",&x);    for(int j = 1;j <= x; ++j)    while(scanf("%c",&src[j]),src[j] < 32);            Splay(Kth(root,now + 1),nil);            Splay(Kth(root,now + 2),root);            root->son[1]->Combine(BuildTree(1,x),false);            root->son[1]->PushUp();            root->PushUp();    }    else if(s[0] == 'D') {    scanf("%d",&x);    Splay(Kth(root,now + 1),nil);    Splay(Kth(root,min(root->size,now + x + 2)),root);    root->son[1]->son[0] = nil;    root->son[1]->PushUp();    root->PushUp();    }    else if(s[0] == 'G') {    scanf("%d",&x);            Splay(Kth(root,now + 1),nil);            Splay(Kth(root,min(now + x + 2,root->size)),root);            Print(root->son[1]->son[0]);            puts("");    }    else if(s[0] == 'P')--now;    else++now;    }    return 0;}void Pretreatment(){    root = BuildTree(1,2);    root->father = nil;    nil->father = nil->son[0] = nil->son[1] = nil;    nil->size = 0;}Complex *BuildTree(int l,int r){    if(l > r)   return nil;    int mid = (l + r) >> 1;    Complex *re = NewComplex(src[mid]);    re->Combine(BuildTree(l,mid - 1),false);    re->Combine(BuildTree(mid + 1,r),true);    re->PushUp();    return re;}Complex *Kth(Complex *a,int k){if(k <= a->son[0]->size)return Kth(a->son[0],k);k -= a->son[0]->size;if(k == 1)return a;return Kth(a->son[1],k - 1);}Complex *NewComplex(char val){Complex *re = new Complex();re->c = val;re->size = 1;re->son[0] = re->son[1] = nil;return re;}inline void Rotate(Complex *a,bool dir){Complex *f = a->father;f->son[!dir] = a->son[dir];f->son[!dir]->father = f;a->son[dir] = f;a->father = f->father;f->father->son[f->Check()] = a;f->father = a;f->PushUp();if(root == f)root = a;}inline void Splay(Complex *a,Complex *aim){while(a->father != aim) {if(a->father->father == aim)Rotate(a,!a->Check());else if(!a->father->Check()) {if(!a->Check())Rotate(a->father,true),Rotate(a,true);elseRotate(a,false),Rotate(a,true);}else {if(a->Check())Rotate(a->father,false),Rotate(a,false);elseRotate(a,true),Rotate(a,false);}}a->PushUp();}void Print(Complex *a){    if(a == nil)    return ;    Print(a->son[0]);    putchar(a->c);    Print(a->son[1]);}

0 0