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;

}