Caves and Tunnels

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <climits>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <vector>
#include <list>
#define rep(i,m,n) for(i=m;i<=n;i++)
#define rsp(it,s) for(set<int>::iterator it=s.begin();it!=s.end();it++)
#define mod 1000000007
#define inf 0x3f3f3f3f
#define vi vector<int>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define ll long long
#define pi acos(-1.0)
#define pii pair<int,int>
#define Lson L, mid, rt<<1
#define Rson mid+1, R, rt<<1|1
const int maxn=1e5+10;
using namespace std;
ll gcd(ll p,ll q){return q==0?p:gcd(q,p%q);}
ll qpow(ll p,ll q){ll f=1;while(q){if(q&1)f=f*p%mod;p=p*p%mod;q>>=1;}return f;}
int n,m,k,t,q,tot,fa[maxn],dep[maxn],son[maxn],h[maxn],bl[maxn],pos[maxn];
struct node
{
    int to,nxt;
}a[maxn<<1];
struct node1
{
    char a[2];
    int x,y;
}op[maxn];
void add(int x,int y)
{
    tot++;
    a[tot].to=y;
    a[tot].nxt=h[x];
    h[x]=tot;
}
void dfs(int now,int pre)
{
    son[now]=1;
    for(int i=h[now];i;i=a[i].nxt)
    {
        if(a[i].to!=pre)
        {
            fa[a[i].to]=now;
            dep[a[i].to]=dep[now]+1;
            dfs(a[i].to,now);
            son[now]+=son[a[i].to];
        }
    }
}
void dfs1(int now,int chain)
{
    int k=0;
    pos[now]=++t;
    bl[now]=chain;
    for(int i=h[now];i;i=a[i].nxt)
    {
        int x=a[i].to;
        if(dep[x]>dep[now]&&son[x]>son[k])
            k=x;
    }
    if(k==0)return;
    dfs1(k,chain);
    for(int i=h[now];i;i=a[i].nxt)
    {
        int x=a[i].to;
        if(dep[x]>dep[now]&&k!=x)
            dfs1(x,x);
    }
}
struct Node
{
    ll Max, lazy;
} T[maxn<<2];

void PushUp(int rt)
{
    T[rt].Max = max(T[rt<<1].Max, T[rt<<1|1].Max);
}

void PushDown(int L, int R, int rt)
{
    int mid = (L + R) >> 1;
    ll t = T[rt].lazy;
    T[rt<<1].Max += t;
    T[rt<<1|1].Max += t;
    T[rt<<1].lazy += t;
    T[rt<<1|1].lazy += t;
    T[rt].lazy = 0;
}

void Update(int l, int r, int v, int L, int R, int rt)
{
    if(l==L && r==R)
    {
        T[rt].lazy += v;
        T[rt].Max += v;
        return ;
    }
    int mid = (L + R) >> 1;
    if(T[rt].lazy) PushDown(L, R, rt);
    if(r <= mid) Update(l, r, v, Lson);
    else if(l > mid) Update(l, r, v, Rson);
    else
    {
        Update(l, mid, v, Lson);
        Update(mid+1, r, v, Rson);
    }
    PushUp(rt);
}
ll Query(int l, int r, int L, int R, int rt)
{
    if(l==L && r== R)
    {
        return T[rt].Max;
    }
    int mid = (L + R) >> 1;
    if(T[rt].lazy) PushDown(L, R, rt);
    if(r <= mid) return Query(l, r, Lson);
    else if(l > mid) return Query(l, r, Rson);
    return max(Query(l, mid, Lson) , Query(mid + 1, r, Rson));
}
ll gao(int x,int y)
{
    ll ma=-1e19;
    while(bl[x]!=bl[y])
    {
        if(dep[bl[x]]<dep[bl[y]])swap(x,y);
        ma=max(ma,Query(pos[bl[x]],pos[x],1,n,1));
        x=fa[bl[x]];
    }
    if(pos[x]>pos[y])swap(x,y);
    ma=max(ma,Query(pos[x],pos[y],1,n,1));
    return ma;
}
int main()
{
    int i,j;
    scanf("%d",&n);
    rep(i,1,n-1)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        add(x,y);
        add(y,x);
    }
    dfs(1,-1);
    dfs1(1,1);
    scanf("%d",&q);
    rep(i,1,q)
    {
        scanf("%s%d%d",op[i].a,&op[i].x,&op[i].y);
        if(op[i].a[0]==‘I‘)Update(pos[op[i].x],pos[op[i].x],op[i].y,1,n,1);
        else printf("%lld\n",gao(op[i].x,op[i].y));
    }
    //system("Pause");
    return 0;
}