if (deep[x]>deep[y]) swap(x,y);
    return max(ans,MAX(1,n,id[x],id[y],1));

    if (x==y) return ans;
    if (dep[x]>dep[y]) swap(x,y);
    return max(ans,ask(1,n,id[x]+1,id[y],1));

 1 #include<cstdio>
 2 #include<iostream>
 3 using namespace std;
 4 const int M=100009;
 5 int n,cnt,t,p[M],hea[M],size[M],v[M],a[M],b[M],c[M],nex[M],dep[M],top[M],id[M],tree[M<<2];
 6 char s[M]; bool vis[M];
 7 
 8 int read()
 9 {
10     int x=0; bool f=0; char ch=getchar();
11     while (ch<‘0‘ || ch>‘9‘) { if (ch==‘-‘) f=1; ch=getchar(); }
12     while (ch>=‘0‘ && ch<=‘9‘) x=(x<<1)+(x<<3)+ch-48,ch=getchar();
13     return f?-x:x;
14 }
15 
16 void add(int x,int y) { v[++cnt]=y,nex[cnt]=hea[x],hea[x]=cnt; }
17 
18 void dfs1(int x,int fa,int h)
19 {
20     size[x]=1,dep[x]=h,p[x]=fa;
21     for (int i=hea[x],y;i;i=nex[i])
22         if ((y=v[i])^fa) dfs1(y,x,h+1),size[x]+=size[y];
23 }
24 
25 void dfs2(int x,int chain)
26 {
27     int i,k=0,y;
28     id[x]=++t,top[x]=chain;
29     for (i=hea[x];i;i=nex[i])
30         if (size[y=v[i]]>size[k] && y^p[x]) k=y;
31     if (!k) return; dfs2(k,chain);
32     for (i=hea[x];i;i=nex[i])
33         if ((y=v[i])^p[x] && k^y) dfs2(y,y);
34 }
35 
36 void push_up(int k) { tree[k]=max(tree[k<<1],tree[k<<1|1]); }
37 
38 void change(int L,int R,int x,int val,int cur)
39 {
40     if (L==R) { tree[cur]=val; return; }
41     int mid=L+R>>1;
42     if (x>mid) change(mid+1,R,x,val,cur<<1|1);
43     else change(L,mid,x,val,cur<<1);
44     push_up(cur);
45 }
46 
47 int ask(int L,int R,int l,int r,int cur)
48 {
49     if (l<=L && R<=r) return tree[cur];
50     int mid=L+R>>1;
51     if (r<=mid) return ask(L,mid,l,r,cur<<1);
52     else if (l>mid) return ask(mid+1,R,l,r,cur<<1|1);
53          else return max(ask(L,mid,l,mid,cur<<1),ask(mid+1,R,mid+1,r,cur<<1|1));
54 }
55 
56 int qry(int x,int y)
57 {
58     int ans=-10000000;
59     for (;top[x]^top[y];x=p[top[x]])
60     {
61         if (dep[top[x]]<dep[top[y]]) swap(x,y);
62         ans=max(ans,ask(1,n,id[top[x]],id[x],1));
63     }
64     if (x==y) return ans;
65     if (dep[x]>dep[y]) swap(x,y);
66     return max(ans,ask(1,n,id[x]+1,id[y],1));
67 }
68 
69 int main()
70 {
71     for (int T=read(),i;T;--T)
72     {
73         n=read(),cnt=t=0;
74         for (i=0;i<=n;++i) hea[i]=0;
75         for (i=1;i<n;++i)
76         {
77             a[i]=read(),b[i]=read(),c[i]=read();
78             add(a[i],b[i]),add(b[i],a[i]);
79         }
80         dfs1(1,1,1),dfs2(1,1);
81         for (i=1;i<n;++i)
82         {
83             if (dep[a[i]]<dep[b[i]]) swap(a[i],b[i]);
84             change(1,n,id[a[i]],c[i],1);
85         }
86         for (;;)
87         {
88             scanf("%s",s);
89             if (s[0]==‘D‘) break;
90             int x=read(),y=read();
91             if (s[0]==‘C‘) change(1,n,id[a[x]],y,1);
92             if (s[0]==‘Q‘) printf("%d\n",qry(x,y));
93         }
94     }
95     return 0;
96 }