COT2

博客已经好久不更新了。
一来是身体差，二来也是没有人看。
再者说自己也比较懒
然后兴致勃勃跑去直接写了个二维bit……
后来觉得不过瘾就去写了个树上莫队QAQ
然后……
因为自己纸张调了一下午。
TAT
其实还是很好懂的，随便找找就能找到资料。

#include <bits/stdc++.h>#define Rep(i,n) for(int i = 1;i <= n;++ i)#define v edge[i].to#define RepG(i,x) for(int i = head[x];~ i;i = edge[i].next)using namespace std;const int N = 100001;struct Edge{int next,to;}edge[N << 1];int B,n,m,rt,cnt,head[N],tim,dfn[N],sz[N],ans,bel[N],dep[N],Ans[N],fa[N],son[N],top[N],stk[N],tot,Top,cur[N];int col[N];bool vis[N];struct Query{int x,y,id;}q[N];bool cmp(Query a,Query b){return bel[a.x] == bel[b.x] ? dfn[a.y] < dfn[b.y] : bel[a.x] < bel[b.x];}void save(int a,int b){edge[cnt] = (Edge){head[a],b},head[a] = cnt ++;}int dfs(int x){    int siz = 0;    sz[x] = 1;dfn[x] = ++ tim;    RepG(i,x)        if(v != fa[x])        {            fa[v] = x;            dep[v] = dep[x] + 1;            siz += dfs(v);            sz[x] += sz[v];            if(sz[son[x]] < sz[v])                son[x] = v;            if(siz >= B)            {                tot ++;                for(int j = 1;j <= siz;++ j)bel[stk[Top --]] = tot;                siz = 0;            }        }    stk[++ Top] = x;    return siz + 1;}void dfs(int x,int tp){    top[x] = tp;    if(!son[x])return;    dfs(son[x],tp);    RepG(i,x)if(v != fa[x] && v != son[x])dfs(v,v);}int LCA(int x,int y){    while(top[x] != top[y])    {        if(dep[top[x]] < dep[top[y]])swap(x,y);        x = fa[top[x]];    }    return dep[x] < dep[y] ? x : y;}void Rev(int x){    vis[x] ^= 1;    if(vis[x])cur[col[x]] ++,ans += (cur[col[x]] == 1);    else cur[col[x]] --,ans -= (!cur[col[x]]);}void Move(int x,int y){    int z = LCA(x,y);    while(x != z)Rev(x),x = fa[x];    while(y != z)Rev(y),y = fa[y];}int b[N];int Bin(int x){    int l = 1,r = n,mid;    while(l < r)    {        mid = l + r >> 1;        if(b[mid] < x)l = mid + 1;        else r = mid;    }    return l;}int main(){//  freopen("data.in","r",stdin);//  freopen("out","w",stdout);    scanf("%d%d",&n,&m);    memset(head,-1,sizeof(head));    B = (int)sqrt(n);    Rep(i,n)scanf("%d",&col[i]),b[i] = col[i];    sort(b + 1,b + 1 + n);    Rep(i,n)col[i] = Bin(col[i]);    for(int i = 1,x,y;i < n;++ i)    {        scanf("%d%d",&x,&y);        save(x,y),save(y,x);    }    rt = 1;    int re = dfs(rt);dfs(rt,rt);    Rep(i,re)bel[stk[Top --]] = tot;    Rep(i,m)    {        scanf("%d%d",&q[i].x,&q[i].y),q[i].id = i;        if(bel[q[i].x] > bel[q[i].y])swap(q[i].x,q[i].y);    }    sort(q + 1,q + 1 + m,cmp);    int lca,x,y;    x = y = 1;    for(int i = 1;i <= m;++ i)    {        Move(q[i].x,x);        Move(q[i].y,y);        x = q[i].x,y = q[i].y;        lca = LCA(x,y);        Rev(lca);        Ans[q[i].id] = ans;        Rev(lca);    }    Rep(i,m)printf("%d\n",Ans[i]);    return 0;}