Hiho 1232 北京网络赛 F Couple Trees

给两颗标号从1...n的树，保证标号小的点一定在上面。每次询问A树上的x点，和B树上的y点同时向上走，最近的相遇点和x,y到这个点的距离。

比赛的时候想用倍增LCA做，但写渣了。。。。后来看到题解是主席树就写了一发

呆马：

 #include <iostream>
 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <cmath>
 #include <vector>
 #define inf 1000000007
 #define maxn 100020
 #define maxm 4200

 using namespace std;

 int fa[maxn],ga[maxn],ll[maxn],rr[maxn],dep[maxn],gap[maxn];
 int n,m,cnt;

 struct node
 {
     node *lc, *rc;
     int key, cov;
     node(){
         key=;
         cov=;
         lc=rc=NULL;
     }
 };

 struct ChairManTree
 {
     node *tree,*rot[maxn];
     int tot;
     node *new_node(){ return &tree[++tot];}
     node *build(int l, int r)
     {
         node *now=new_node();
         now->cov=now->key=;
         if (l==r) return now;
         int mid=(l+r)>>;
         now->lc=build(l,mid);
         now->rc=build(mid+,r);
         return now;
     }

     void down(node *p)
     {
         if (p->cov)
         {
             node *nl=new_node();
             node *nr=new_node();
             *nl=*p->lc;
             *nr=*p->rc;
             nl->key=max(p->lc->key,p->cov);
             nl->cov=max(p->lc->cov,p->cov);
             nr->key=max(p->rc->key,p->cov);
             nr->cov=max(p->rc->cov,p->cov);
             p->lc=nl;
             p->rc=nr;
             p->cov=;
         }
     }

     node *change(node *p, int l, int r, int ll, int rr, int x)
     {
         node *now=new_node();
         if (ll<=l && r<=rr)
         {
             *now=*p;
             now->key=max(now->key,x);
             now->cov=max(now->cov,x);
             return now;
         }
         down(p);
         *now=*p;
         int mid=(l+r)>>;
         if (ll<=mid) now->lc=change(p->lc, l, mid, ll, rr, x);
         if (rr>mid) now->rc=change(p->rc, mid+, r, ll, rr, x);
         return now;
     }

     int query(node *now, int l, int r, int x)
     {
         if (l==r) return now->key;
         down(now);
         int mid=(l+r)>>;
         if (x<=mid) return query(now->lc, l, mid, x);
         else return query(now->rc, mid+, r, x);
     }

     void write(node *now,int l,int r)
     {
         if (l==r)
         {
             cout<<now->key;
             return ;
         }
         down(now);
         int mid=(l+r)>>;
         write(now->lc,l,mid);
         write(now->rc,mid+,r);
     }

     void init(int n)
     {
         tree=new node[n*];
         tot=;
     }
     void clear()
     {
         delete [] tree;
     }
 }s;

 vector<int> e[maxn];

 void dfs(int x)
 {
     ll[x]=++cnt;
     int n=e[x].size();
     for (int i=;i<n;i++)
     {
         int k=e[x][i];
         dfs(k);
     }
     rr[x]=cnt;
 }

 int main()
 {
     //freopen("F.in","r",stdin);
     while (scanf("%d%d",&n,&m)!=EOF)
     {
         s.init(n);
         fa[]=ga[]=;
         dep[]=gap[]=;
         for (int i=;i<=n;i++) e[i].clear();
         for (int i=;i<=n;i++) scanf("%d",&fa[i]), e[fa[i]].push_back(i), dep[i]=dep[fa[i]]+;
         for (int i=;i<=n;i++) scanf("%d",&ga[i]), gap[i]=gap[ga[i]]+;
         cnt=;
         dfs();

         s.rot[]=s.build(,n);

         for (int i=;i<=n;i++)
             s.rot[i]=s.change(s.rot[ga[i]],,n,ll[i],rr[i],i);
         int x,y,ans=;
         for (int i=;i<=m;i++)
         {
             scanf("%d%d",&x,&y);
             x=(x+ans)%n+, y=(y+ans)%n+;
             ans=s.query(s.rot[y],,n,ll[x]);
             printf("%d %d %d\n",ans,dep[x]-dep[ans]+, gap[y]-gap[ans]+);
         }
         s.clear();
     }
     return ;
 }

couple tree