BZOJ 5338: [TJOI2018]xor 可持久化trie+dfs序

强行把序列问题放树上，好无聊啊~

code:

#include <bits/stdc++.h>
#define N 200005
#define setIO(s) freopen(s".in","r",stdin)
using namespace std;
int tot,edges,tim;
int cnt[N*33],ch[N*33][2],tree[N],seq[N],val[N],ba[N];
int fa[N],son[N],size[N],top[N],dep[N],hd[N],to[N<<1],nex[N<<1],dfn[N],ed[N];
inline void add(int u,int v)
{
    nex[++edges]=hd[u],hd[u]=edges,to[edges]=v;
}
void insert(int pre,int &x,int v)
{
    int now=x=++tot;
    for(int i=30;i>=0;--i)
    {
        int o=((v>>i)&1);
        ch[now][o^1]=ch[pre][o^1];
        ch[now][o]=++tot;
        pre=ch[pre][o];
        now=tot;
        cnt[now]=cnt[pre]+1;
    }
}
void dfs1(int u,int ff)
{
    fa[u]=ff,dep[u]=dep[ff]+1,size[u]=1,dfn[u]=++tim,ba[tim]=u;
    for(int i=hd[u];i;i=nex[i])
    {
        int v=to[i];
        if(v==ff)    continue;
        insert(tree[u],tree[v],val[v]);
        dfs1(v,u);
        size[u]+=size[v];
        if(size[v]>size[son[u]])       son[u]=v;
    }
    ed[u]=tim;
}
void dfs2(int u,int tp)
{
    top[u]=tp;
    if(son[u])    dfs2(son[u],tp);
    for(int i=hd[u];i;i=nex[i])     if(to[i]!=fa[u]&&to[i]!=son[u])   dfs2(to[i],to[i]);
}
inline int LCA(int x,int y)
{
    while(top[x]!=top[y])    dep[top[x]]>dep[top[y]]?x=fa[top[x]]:y=fa[top[y]];
    return dep[x]<dep[y]?x:y;
}
int query1(int x,int y,int z)
{
    int re=0;
    for(int i=30;i>=0;--i)
    {
        int o=((z>>i)&1);
        if(cnt[ch[y][o^1]]>cnt[ch[x][o^1]])
        {
            re+=(1<<i);
            y=ch[y][o^1];
            x=ch[x][o^1];
        }
        else
        {
            y=ch[y][o];
            x=ch[x][o];
        }
    }
    return re;
}
int query2(int x,int y,int lca,int ff,int z)
{
    int re=0;
    for(int i=30;i>=0;--i)
    {
        int o=((z>>i)&1);
        if(cnt[ch[x][o^1]]+cnt[ch[y][o^1]]-cnt[ch[lca][o^1]]-cnt[ch[ff][o^1]])
        {
            re+=(1<<i);
            x=ch[x][o^1];
            y=ch[y][o^1];
            lca=ch[lca][o^1];
            ff=ch[ff][o^1];
        }
        else
        {
            x=ch[x][o];
            y=ch[y][o];
            lca=ch[lca][o];
            ff=ch[ff][o];
        }
    }
    return re;
}
int main()
{
    // setIO("input");
    int i,j,n,m;
    scanf("%d%d",&n,&m);
    for(i=1;i<=n;++i)      scanf("%d",&val[i]);
    for(i=1;i<n;++i)
    {
        int x,y;
        scanf("%d%d",&x,&y),   add(x,y), add(y,x);
    }
    insert(tree[0],tree[1],val[1]);
    dfs1(1,0);
    dfs2(1,1);
    for(i=1;i<=tim;++i)      insert(seq[i-1],seq[i],val[ba[i]]);
    while(m--)
    {
        int op,x,y,z;
        scanf("%d",&op);
        if(op==1)
        {
            scanf("%d%d",&x,&y);
            printf("%d\n",query1(seq[dfn[x]-1],seq[ed[x]],y));
        }
        else
        {
            scanf("%d%d%d",&x,&y,&z);
            int t=LCA(x,y);
            printf("%d\n",query2(tree[x],tree[y],tree[t],tree[fa[t]],z));
        }
    }
    return 0;
}