QtreeⅠ

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
using namespace std;
const int Mx=10010;
struct Edge { int x,y,val; } edge[Mx];
struct Tree { int l,r,val; } tree[4*Mx];
int n,cnt,dep[Mx],siz[Mx],fa[Mx],num[Mx],son[Mx],top[Mx];//top表示最近的重链父节点 
int tot,nxt[2*Mx],head[Mx],ver[2*Mx],val[2*Mx];
void clear()
{
    memset(head,0,sizeof(head));
    memset(son,0,sizeof(son));
    cnt=0;tot=0;
}
inline void add(int x,int y,int z)
{
    tot++;
    nxt[tot]=head[x];
    ver[tot]=y;
    val[tot]=z;
    head[x]=tot;    
}
//链剖 
void dfs1(int u,int Fa,int Dep)
{
    dep[u]=Dep,siz[u]=1,son[u]=0,fa[u]=Fa;
    for(int i=head[u];i;i=nxt[i])
    {
        int v=ver[i];
        if(v==Fa) continue;
        dfs1(v,u,Dep+1);
        siz[u]+=siz[v];
        if(siz[son[u]]<siz[v]) son[u]=v;
    }
}
void dfs2(int u,int Top)
{
    top[u]=Top,num[u]=++cnt;
    if(son[u]) dfs2(son[u],Top);
    for(int i=head[u];i;i=nxt[i])
    {
        int v=ver[i];
        if(v!=fa[u]&&v!=son[u]) dfs2(v,v);
    }
}
//线段树 
void pushup(int x) { tree[x].val=max(tree[x<<1].val,tree[x<<1|1].val); }
void build(int l,int r,int v)
{
    tree[v].l=l;tree[v].r=r;
    if(l==r) { tree[v].val=val[l]; return ; }
    int mid=(l+r)>>1;
    build(l,mid,v*2); build(mid+1,r,v*2+1);
    pushup(v);
}
void update(int u,int v,int val)
{
    if(tree[u].l==tree[u].r) { tree[u].val=val; return ; }
    int mid=(tree[u].l+tree[u].r)/2;
    if(v<=mid) update(u*2,v,val);
    else update(u*2+1,v,val);
    pushup(u);
}
int query(int x,int l, int r)
{
    if(tree[x].l>=l&&tree[x].r<=r) return tree[x].val;
    int ans=0,mid=(tree[x].l+tree[x].r)/2;
    if(l<=mid) ans=max(ans,query(x<<1,l,r));
    if(r>mid) ans=max(ans,query(x<<1|1,l,r));
    return ans;
}
int solve(int u,int v)
{
    int ans=0,Top1=top[u],Top2=top[v];
    while(Top1!=Top2)
    {
        if(dep[Top1]<dep[Top2]) swap(Top1,Top2),swap(u,v);
        ans=max(ans,query(1,num[Top1],num[u]));
        u=fa[Top1];Top1=top[u];
    }
    if(u==v) return ans;
    if(dep[u]>dep[v]) swap(u,v);
    ans=max(ans,query(1,num[son[u]],num[v]));
    return ans;
}
int main()
{
    int T;scanf("%d",&T);
    while(T--)
    {
        clear();
        scanf("%d",&n);
        for(int i=1,x,y,z;i<n;i++)
        {
            scanf("%d%d%d",&x,&y,&z);
            edge[i].x=x;edge[i].y=y;edge[i].val=z;
            add(x,y,z);add(y,x,z);
        }
        dfs1(1,0,1);dfs2(1,1);
        for(int i=1;i<n;i++)
        {
            if(dep[edge[i].x]<dep[edge[i].y]) swap(edge[i].x,edge[i].y);
            val[num[edge[i].x]]=edge[i].val;
        }
        build(1,cnt,1);
        while(1)
        {
            char s[200];scanf("%s",s);if(s[0]==‘D‘) break;
            int x,y; scanf("%d%d",&x,&y);
            if(s[0]==‘Q‘) printf("%d\n",solve(x,y));
            if (s[0]==‘C‘) update(1,num[edge[x].x],y);
        }
    }
　　 return 0;
}