我感觉我树上启发式合并写的挺标准的，为什么过不了~

求大佬帮忙看看：

#include <bits/stdc++.h>
using namespace std;
const int maxn = 100010;
int n, m, sz[maxn], c[maxn], cnt[maxn];
bool big[maxn];
vector<int> g[maxn];

/**
    res[u] 表示 u 对应的答案
    ap[i] 表示目前出现次数等于i的颜色编号和
    apid 表示目前出现次数最多的颜色的出现次数
*/
long long res[maxn], ap[maxn];
int apid;

void add(int u, int p, int x) {

    int cc = cnt[ c[u] ];
    ap[cc] -= c[u];
    ap[cc+x] += c[u];
    if (x > 0 && apid < cc+x) apid = cc+x;
    if (x < 0 && cc == apid && ap[cc] == 0) apid --;

    cnt[ c[u] ] += x;
    for (vector<int>::iterator it = g[u].begin(); it != g[u].end(); it ++) {
        int v = *it;
        if (v != p && !big[v])
            add(v, u, x);
    }
}
void dfs(int u, int p, bool keep) {
    int mx = -1, bigSon = -1;   // mx表示重儿子的sz, bigSon表示重儿子编号
    for (vector<int>::iterator it = g[u].begin(); it != g[u].end(); it ++) {
        int v = *it;
        if (v != p && sz[v] > mx)
            mx = sz[ bigSon = v ];
    }
    for (vector<int>::iterator it = g[u].begin(); it != g[u].end(); it ++) {
        int v = *it;
        if (v != p && v != bigSon)
            dfs(v, u, false);
    }

    if (bigSon != -1)
        dfs(bigSon, u, true),
        big[bigSon] = true;
    add(u, p, 1);
    res[u] = ap[apid];
    if (bigSon != -1)
        big[bigSon] = 0;
    if (!keep)
        add(u, p, -1);
}
int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i ++) scanf("%d", c+i);
    for (int i = 1; i < n; i ++) {
        int a, b;
        scanf("%d%d", &a, &b);
        g[a].push_back(b);
        g[b].push_back(a);
    }
    dfs(1, -1, false);
    for (int i = 1; i <= n; i ++) printf("%d ", res[i]);
    return 0;
}