bzoj3223 文藝平衡樹

傳送門 :http://www.lydsy.com/JudgeOnline/problem.php?id=3223
splay區間翻轉的基礎題,然而我還是調了一晚上(蒟蒻的悲哀)

#include <cstdio>
#include <cmath>
#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
int n,m,root,x,y;
int ls[100005],rs[100005],s[100005],v[100005],lazy[100005],fa[100005],f[100005];
void pushup(int rt)
{
    s[rt]=s[ls[rt]]+s[rs[rt]]+1;
}
void pushdown(int rt)
{
    if (!lazy[rt]) return;
    swap(ls[rt],rs[rt]);
    lazy[ls[rt]]^=1;
    lazy[rs[rt]]^=1;
    lazy[rt]=0;
}
void build(int l,int r,int fa)
{
    if (l>r) return;
    int now=v[l];
    int last=v[fa];
    if (l==r)
    {
        s[now]=1;
        f[now]=last;
        if (l<fa) ls[last]=now;
        else rs[last]=now;
        return;
    }
    int mid=(l+r)>>1;
    now=v[mid];
    build(l,mid-1,mid);
    build(mid+1,r,mid);
    f[now]=last;
    if (mid<fa)  ls[last]=now;
    else rs[last]=now;      
    pushup(mid);
}
void zig(int x)
{
    int y=f[x],z=f[y];
    if (ls[z]==y) ls[z]=x;
    else rs[z]=x;
    f[x]=z;
    f[y]=x;
    ls[y]=rs[x];
    f[rs[x]]=y;
    rs[x]=y;
    pushup(y);
    pushup(x);
    if (y==root) root=x;
}
void zag(int x)
{
    int y=f[x],z=f[y];
    if (ls[z]==y) ls[z]=x;
    else rs[z]=x;
    f[x]=z;
    f[y]=x;
    rs[y]=ls[x];
    f[ls[x]]=y;
    ls[x]=y;
    pushup(y);
    pushup(x);
    if (y==root) root=x;
}
void splay(int x,int k)
{
    while(f[x]!=k)
    {
        if (ls[f[x]]==x) zig(x);
        else zag(x);
    }
}
int find(int &k,int x)
{
    pushdown(k);
    if(s[ls[k]]+1==x)return k;
    if(s[ls[k]]>=x)return find(ls[k],x);
    return find(rs[k],x-s[ls[k]]-1);
}
void lazye(int l,int r)
{
    int x=find(root,l);
    int y=find(root,r);
    splay(x,0);
    splay(y,x);
    lazy[ls[y]]^=1;
}
int main()
{
    scanf("%d%d",&n,&m);
    for (int i=1;i<=n+2;i++)
    {
        v[i]=i;
    }
    root=(n+3)>>1;
    build(1,n+2,0);
    for (int i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        lazye(x,y+2);
    }
    for (int i=2;i<=n+1;i++)
    {
        printf("%d ",find(root,i)-1);
    }
}