虽然这题是树链刨分，但我线段树查询寄了,求调

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>

using namespace std;

const int N = 1e5 + 4, INF = 1e5;

struct Tree {
    int l, r;
    int sum, maxx;
}tr[N * 4];

int n, m;
int w[N], h[N], e[N], ne[N], idx;
int dep[N], sz[N], top[N], cnt, fa[N], son[N], id[N], v[N];

void add(int a, int b) {
    ne[idx] = h[a], e[idx] = b, h[a] = idx ++;
}

void dfs1(int u, int father, int depth) {
    dep[u] = depth, fa[u] = father, sz[u] = 1;
    for(int i = h[u]; ~i; i = ne[i]) {
        int j = e[i];
        if(j == father) continue;
        dfs1(j, u, depth + 1);
        sz[u] += sz[j];
        if(sz[j] > sz[son[u]]) son[u] = j;
    }
}

void dfs2(int u, int t) {
    id[u] = ++ cnt, v[cnt] = w[u], top[u] = t;
    if(!son[u]) return;
    dfs2(son[u], t);
    for(int i = h[u]; ~i; i = ne[i]) {
        int j = e[i];
        if(j == fa[u] || j == son[u]) continue;
        dfs2(j, j);
    }
}

void pushup(int u) {
    tr[u].sum = tr[u << 1].sum + tr[u << 1 | 1].sum;
    tr[u].maxx = max(tr[u << 1].maxx, tr[u << 1 | 1].maxx);
}

void build(int u, int l, int r) {
    tr[u] = {l, r, v[l], v[l]};
    if(l == r) return;
    int mid = l + r >> 1;
    build(u << 1, l, mid), build(u << 1 | 1, mid + 1, r);
    pushup(u);
}

void update(int u, int p, int x) {
    if(tr[u].l == tr[u].r && tr[u].r == p) {
        tr[u].maxx = tr[u].sum = x;
        return;
    }
    int mid = tr[x].l + tr[x].r >> 1;
    if(p <= mid) update(u << 1, p, x);
    else update(u << 1 | 1, p, x);
    pushup(u);
}

int main() {
    
    memset(h, -1, sizeof h);
    cin >> n;
    
    for(int i = 0; i < n - 1; ++ i) {
        int a, b;
        cin >> a >> b;
        add(a, b), add(b, a);
    }
    
    for(int i = 1; i <= n; ++ i) cin >> w[i];
    
    dfs1(1, -1, 1);
    dfs2(1, 1);
    build(1, 1, n);
    
    update(1, 3, 11);
    
    return 0;
}