SGU 187.Twist and whirl - want to cheat

splay

不过竟然用reverse一发水过了。。。

调用STL的代码：(156ms)

#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
int f[130009];
int n,m,l,r;
int main(){
       scanf("%d %d",&n,&m);
       for(int i=1;i<=n;i++) f[i]=i;
       for(int i=1;i<=m;i++){
              scanf("%d %d",&l,&r);
              reverse(f+l,f+r+1);
       }
       for(int i=1;i<=n;i++)
              printf("%d ",f[i]);
}

　　

Splay(46ms)(代码来自网络)

#include<cstdio>
#include<algorithm>
const int MAXn=130000+9;
struct splay_tree
{
        int l[MAXn],r[MAXn],f[MAXn],n,root;
        int size[MAXn];
        bool re[MAXn];
        void push(int u)
        {
                if(re[u])
                {
                        re[u]=0;
                        if(l[u])
                                re[l[u]]^=1;
                        if(r[u])
                                re[r[u]]^=1;
                        std::swap(l[u],r[u]);
                }
        }
        void update(int u)
        {
                size[u]=size[l[u]]+size[r[u]]+1;
        }
        void rotate(int x)
        {
                int y=f[x];
                push(y);
                push(x);
                f[x]=f[y];
                if(f[y])
                {
                        if(l[f[y]]==y)
                                l[f[y]]=x;
                        else
                                r[f[y]]=x;
                }
                f[y]=x;
                if(x==r[y])
                {
                        if(l[x])
                                f[l[x]]=y;
                        r[y]=l[x];
                        l[x]=y;
                }
                else
                {
                        if(r[x])
                                f[r[x]]=y;
                        l[y]=r[x];                
                        r[x]=y;
                }
                update(y);
                update(x);
        }
        void splay(int u,int aim)
        {
                int t;
                while((t=f[u])!=aim)
                        if(f[t]==aim)
                                rotate(u);
                        else if((l[f[t]]==t)==(l[t]==u))
                                rotate(t),rotate(u);
                        else rotate(u),rotate(u);
                if(!aim)
                        root=u;
        }
        void build(int num)
        {
                size[0]=0;
                re[0]=0;
                n=num;
                root=1;
                for(int i=1;i<=n;++i)
                {
                        l[i]=0;
                        r[i]=i+1;
                        f[i]=i-1;
                        size[i]=n-i+1;
                        re[i]=0;
                }
                r[n]=0;
                splay(n,0);
        }
        int find(int rank)
        {
                if(!rank || rank>n)
                        return 0;
                for(int u=root;;)
                {
                        push(u);
                        if(size[l[u]]+1==rank)
                        {
                                splay(u,0);        
                                return u;
                        }
                        else if(rank<=size[l[u]])
                                u=l[u];
                        else
                        {
                                rank-=size[l[u]]+1;
                                u=r[u];
                        }
                }
        }
        void reserve(int a,int b)
        {
                int pre=find(a-1),suf=find(b+1);
                if(pre)
                {
                        splay(pre,0);
                        if(suf)
                        {
                                splay(suf,pre);
                                re[l[suf]]^=1;
                        }
                        else re[r[pre]]^=1;
                }
                else if(suf)
                {
                        splay(suf,0);
                        re[l[suf]]^=1;
                }
                else re[root]^=1;
        }
        void print(int u)
        {
                for(;u;u=r[u])
                {
                        push(u);
                        print(l[u]);
                        printf("%d ",u);
                }
        }
}tree;
int main()
{
        #ifndef ONLINE_JUDGE
        freopen("in.txt","r",stdin);freopen("out.txt","w",stdout);
        #endif
        int n,m,i,j,k;
        scanf("%d%d",&n,&m);
        tree.build(n);
        for(i=1;i<=m;++i)
        {
                scanf("%d%d",&j,&k);
                tree.reserve(j,k);
        }
        tree.print(tree.root);
        return 0;
}