rt，本人用的线段树二分，结果 70 分，求调

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 1e6 + 1;
int n, k, a[N], rd[N], rt;
ll ans;
vector<int> g[N];
bool vis[N];
struct SegmentTree
{
    int Or[N << 2];
    int ls(int x) { return x << 1; }
    int rs(int x) { return (x << 1) | 1; }
    void init() { memset(Or, 0, sizeof Or); }
    SegmentTree() { init(); }
    void modify(int x, int l, int r, int pos, int val)
    {
        if (l == r)
            return Or[x] = val, void();
        int mid = (l + r) >> 1;
        if (pos <= mid)
            modify(ls(x), l, mid, pos, val);
        else
            modify(rs(x), mid + 1, r, pos, val);
        Or[x] = Or[ls(x)] | Or[rs(x)];
    }
    int query(int x, int l, int r, int k, int pre)
    {
        if (Or[1] < k)
            return 0;
        if (l == r)
            return l;
        int mid = (l + r) >> 1;
        if ((pre | Or[rs(x)]) >= k)
            return query(rs(x), mid + 1, r, k, pre);
        return query(ls(x), l, mid, k, pre | Or[rs(x)]);
    }
} sgt;
template <typename T>
void read(T &x)
{
    x = 0;
    T f = 1;
    char c = getchar();
    for (; !isdigit(c); c = getchar())
        if (c == '-')
            f = -1;
    for (; isdigit(c); c = getchar())
        x = (x << 3) + (x << 1) + c - 48;
    x *= f;
}
template <typename T>
void write(T x)
{
    if (x > 9)
        write(x / 10);
    putchar(x % 10 + 48);
}
template <typename T>
void print(T x, char ed = '\n')
{
    if (x < 0)
        putchar('-'), x = -x;
    write(x), putchar(ed);
}
void dfs(int u, int dep)
{
    sgt.modify(1, 1, n, dep, a[u]), ans += 1ll * sgt.query(1, 1, n, k, 0);
    for (int v : g[u])
        dfs(v, dep + 1);
    sgt.modify(1, 1, n, dep, 0);
}
signed main()
{
    read(n), read(k);
    for (int i = 1; i <= n; i++)
        read(a[i]);
    for (int i = 1, u, v; i < n; i++)
        read(u), read(v), g[u].emplace_back(v), vis[v] = 1;
    for (int i = 1; i <= n; i++)
    {
        if (!vis[i])
        {
            rt = i;
            break;
        }
    }
    dfs(rt, 1), print(ans);
    return 0;
}