简单题，看题目就懂。
#include<queue>
#include<stack>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define INF 99999999
#define ll __int64
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
using namespace std;
const int MAXN = ;
struct node
{
int to;
int v;
int next;
}edge[MAXN*];
int pre[MAXN],ind,top[MAXN],fa[MAXN],son[MAXN],w[MAXN],deq[MAXN],siz[MAXN],fn;
int tree[MAXN<<],val[MAXN],n;
void add(int x,int y)
{
edge[ind].to = y;
edge[ind].next = pre[x];
pre[x] = ind++;
} //第一次搜索找出siz[],son[],deq[],fa[]
void dfs1(int rt,int pa,int d)
{
deq[rt] = d;
son[rt] = ;
fa[rt] = pa;
siz[rt] = ;
int i;
for(i=pre[rt]; i!=-; i=edge[i].next){
int t = edge[i].to;
if(t != fa[rt]){
dfs1(t,rt,d+);
siz[rt] += siz[t];
if(siz[son[rt]] < siz[t]){//如果父节点的son[rt]的iz[]小于子节点的siz[]更新son[]
son[rt] = t;
}
}
}
} //第二次搜索找到w[],top[]
void dfs2(int rt,int tp)
{
top[rt] = tp;
w[rt] = ++fn; if(son[rt] != )
dfs2(son[rt],tp);//如果当前父节点纯在son 那么为了让链在线段树中连续 先对son[]进行搜索，并且重边顶端的点相同。 for(int i=pre[rt]; i!=-; i=edge[i].next){
int t = edge[i].to;
if(t != fa[rt] && son[rt] != t){
dfs2(t,t);
}
}
} /******************************/ void pushup(int rt)
{
tree[rt] = tree[rt<<]+tree[rt<<|];
}
void Insert(int p,int v,int l,int r,int rt)
{
if(l == r){
tree[rt] = v;
return ;
}
int m = (l+r)/;
if(m >= p){
Insert(p,v,lson);
}
else{
Insert(p,v,rson);
}
pushup(rt);
}
void updata(int p,int v,int l,int r,int rt)
{
if(l == r){
tree[rt] = v;
return ;
}
int m = (l+r)/;
if(m >= p){
updata(p,v,lson);
}
else {
updata(p,v,rson);
}
pushup(rt);
}
int query(int L,int R,int l,int r,int rt)
{
if(L<=l && r<=R){
return tree[rt];
}
int m = (l+r)/;
int ans = ;
if(m >= L){
ans += query(L,R,lson);
}
if(m < R){
ans += query(L,R,rson);
}
return ans;
}
int lca(int x,int y)
{
int ans = ;
while(top[x] != top[y])
{
if(deq[top[x]] < deq[top[y]]){
swap(x,y);
}
ans += query(w[top[x]],w[x],,fn,); x = fa[top[x]];
} //注意线段和点之间的差别 if(deq[x] < deq[y]){
swap(x,y);
}
return ans+query(w[y],w[x],,fn,);
}
int main()
{
int i,j,t,ff = ;
scanf("%d",&t);
while(t--)
{
scanf("%d",&n);
for(i=; i<=n; i++){
scanf("%d",&val[i]);
}
ind = ;
memset(pre,-,sizeof(pre));
for(i=; i<n; i++){ int x,y;
scanf("%d%d",&x,&y);
add(x+,y+);
add(y+,x+);
}
memset(tree,,sizeof(tree));
dfs1(,,);
fn = ;
dfs2(,); for(i=; i<=n; i++){
Insert(w[i],val[i],,fn,);
} int ft;
scanf("%d",&ft);
printf("Case %d:\n",++ff);
while(ft--)
{
int flag;
scanf("%d",&flag);
if(flag == ){
int x,y;
scanf("%d%d",&x,&y);
x++;
updata(w[x],y,,fn,);
}
else {
int x,y;
scanf("%d%d",&x,&y);
x++;
y++;
printf("%d\n",lca(x,y));
}
}
}
}