有没有好心人帮忙看下为什么RE

spoj上过了，数组大小也改了，但是只有前4组后6组全都RE。

#include<bits/stdc++.h>
#define OL(o) o<<1
#define OR(o) o<<1|1
const int MAXN = 1e6;
const int INF = 2147483000;
using namespace std;
inline int Read() {
    int x=0,f=1;
    char ch=getchar();
    while(!isdigit(ch)) {
        if(ch == '-')f=-1;
        ch=getchar();
    }
    while(isdigit(ch)) {
        x=x*10+ch-'0';
        ch=getchar();
    }
    return f*x;
}
struct node {
    int v,w,next;
} E[MAXN*2+10];
int head[MAXN+10],e;
inline void insert(int u,int v,int w) {
    E[++e].v=v;
    E[e].w=w;
    E[e].next=head[u];
    head[u]=e;
}
int T,N;
int K[MAXN+10],fa[MAXN+10],Son[MAXN+10];
int Top[MAXN+10],Dfn[MAXN+10],Deep[MAXN+10],dfs_clock;
int A[MAXN+10];
int tree[MAXN*10+10];
pair<int,int>road[MAXN+10];
inline void buildtree(int o,int l,int r) {
    if(l == r) {
        tree[o]=A[l];
        return ;
    }
    int mid = (l+r)>>1;
    buildtree(OL(o),l,mid);
    buildtree(OR(o),mid+1,r);
    tree[o]=max(tree[OL(o)],tree[OR(o)]);
}
int treequery(int o,int l,int r,int ql,int qr) {
    if(l>=ql&&r<=qr)return tree[o];
    int mid = (l+r)>>1;
    int p1=-INF,p2=-INF;
    if(ql<=mid)p1=treequery(OL(o),l,mid,ql,qr);
    if(qr>mid)p2=treequery(OR(o),mid+1,r,ql,qr);
    return max(p1,p2);
}
inline void updata(int o,int l,int r,int p,int v) {
    if(l == r) {
        tree[o]=v;
        return ;
    }
    int mid = (l+r)>>1;
    if(p<=mid)updata(OL(o),l,mid,p,v);
    else updata(OR(o),mid+1,r,p,v);
    tree[o]=max(tree[OL(o)],tree[OR(o)]);
}
inline void dfs1(int u) {
    int maxn = -INF;
    for(int i=head[u]; i; i=E[i].next) {
        int v=E[i].v,w=E[i].w;
        if(v == fa[u])continue;
        fa[v]=u;
        Deep[v]=Deep[u]+1;
        dfs1(v);
        K[u]+=K[v];
        if(K[v]>maxn) {
            Son[u]=v;
            maxn=K[v];
        }
    }
}
inline void dfs2(int u,int anc) {
    Dfn[u]=++dfs_clock;
    Top[u]=anc;
    if(Son[u])dfs2(Son[u],anc);
    for(int i=head[u]; i; i=E[i].next) {
        int v=E[i].v,w=E[i].w;
        if(v == Son[u]) {
            A[Dfn[v]]=w;
            continue;
        }
        if(v == fa[u])continue;
        dfs2(v,v);
        A[Dfn[v]]=w;
    }
}
inline void dfs3(int u) {
    for(int i=head[u]; i; i=E[i].next) {
        int v=E[i].v,w=E[i].w;
        if(v == fa[u])continue;
        A[Dfn[v]]=w;
        dfs3(v);
    }
}
inline void prepare() {
    dfs1(1),dfs2(1,1);
    buildtree(1,1,N);
}
int HLDquery(int u,int v) {
    int ret = 0;
    while(Top[u] != Top[v]) {
        if(Deep[Top[u]]<Deep[Top[v]])swap(u,v);
        ret = max(ret,treequery(1,1,N,Dfn[Top[u]],Dfn[u]));
        u=fa[Top[u]];
    }
    if(Dfn[u]<Dfn[v])swap(u,v);
    ret = max(ret,treequery(1,1,N,Dfn[v]+1,Dfn[u]));
    return ret;
}
int main() {
    char q[10];
    N=Read();
    int u,v,w,p;
    for(int i=1; i<N; i++) {
        u=Read(),v=Read(),w=Read();
        insert(u,v,w);
        insert(v,u,w);
        road[i]=make_pair(u,v);
    }
    prepare();
    scanf("%s",q);
    while(q[0] != 'D') {
        if(q[0] == 'C') {
            p=Read(),w=Read();
            u=road[p].first,v=road[p].second;
            if(Dfn[u]<Dfn[v])swap(u,v);
            updata(1,1,N,Dfn[u],w);
        }
        if(q[0] == 'Q') {
            u=Read(),v=Read();
            printf("%d\n",HLDquery(u,v));
        }
        scanf("%s",q);
    }
    return 0;
}