UVA 11922 splay

来源：互联网发布：yii2 cms 编辑：程序博客网时间：2024/06/05 15:47

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题意：给n个数，1到n，然后每个操作a，b是将a到b的所有数翻转后添加到末尾

思路：白书的例题，代码参考这位大神的

#include <stdio.h>#include <string.h>#include <stdlib.h>#include <iostream>#include <algorithm>using namespace std;typedef long long ll;typedef unsigned long long ull;const int inf=0x3f3f3f3f;const ll INF=0x3f3f3f3f3f3f3f3fll;const int maxn=1e5+10;struct Node{    Node *ch[2];    int v,s,flip;    Node(int v):v(v){ch[0]=ch[1]=NULL;s=1;flip=0;}    int cmp(int x) const{        int d=x-(ch[0]==NULL?0:ch[0]->s);        if(d==1) return -1;        return d<=0?0:1;    }    void maintain(){        s=1;if(ch[0]!=NULL) s+=ch[0]->s;        if(ch[1]!=NULL) s+=ch[1]->s;    }    void pushdown(){        if(flip){            flip=0;            swap(ch[0],ch[1]);            if(ch[0]!=NULL) ch[0]->flip=!ch[0]->flip;            if(ch[1]!=NULL) ch[1]->flip=!ch[1]->flip;        }    }};void Rotate(Node* &o,int d){    Node* k=o->ch[d^1];o->ch[d^1]=k->ch[d];k->ch[d]=o;    o->maintain();k->maintain();o=k;}void build(Node* &o,int l,int r){    if(l>r) return ;    int mid=(l+r)>>1;    o=new Node(mid);    build(o->ch[0],l,mid-1);    build(o->ch[1],mid+1,r);    o->maintain();}void pri(Node* &o){    o->pushdown();    if(o->ch[0]!=NULL) pri(o->ch[0]);    if(o->v) printf("%d\n",o->v);    if(o->ch[1]!=NULL) pri(o->ch[1]);}void removetree(Node* &x){    if(x->ch[0]!=NULL) removetree(x->ch[0]);    if(x->ch[1]!=NULL) removetree(x->ch[1]);    delete x;x=NULL;}void splay(Node* &o,int k){    o->pushdown();    int d=o->cmp(k);    if(d==1) k-=(o->ch[0]==NULL?0:o->ch[0]->s)+1;    if(d!=-1){        Node* p=o->ch[d];        p->pushdown();        int d2=p->cmp(k);        int k2=(d2==0?k:k-(p->ch[0]==NULL?0:p->ch[0]->s)-1);        if(d2!=-1){            splay(p->ch[d2],k2);            if(d==d2) Rotate(o,d^1);            else Rotate(o->ch[d],d);        }        Rotate(o,d^1);    }}Node* Merge(Node* L,Node* R){    splay(L,L->s);    L->ch[1]=R;    L->maintain();    return L;}void split(Node* o,int k,Node* &L,Node* &R){    splay(o,k);    L=o;R=o->ch[1];    o->ch[1]=NULL;    L->maintain();}void debug(Node* r){    if (r==NULL)return;    printf("key:%d lson:%d rson:%d\n",r->v,r->ch[0]->v,r->ch[1]->v);    debug(r->ch[0]);    debug(r->ch[1]);}int main(){    int n,m,x,y;    while(scanf("%d%d",&n,&m)!=-1){        Node *root=NULL;        Node *l,*r,*mid,*o;        build(root,0,n);        while(m--){            scanf("%d%d",&x,&y);            split(root,x,l,o);            split(o,y-x+1,mid,r);            mid->flip^=1;            root=Merge(Merge(l,r),mid);        }        pri(root);        removetree(root);    }    return 0;}

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