C++题解

#include <iostream>
#include <vector>
using namespace std;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<int> color(n + 1);
    for (int i = 1; i <= n; ++i) {
        cin >> color[i];
    }
    
    vector<vector<int>> adj(n + 1);
    for (int i = 1; i < n; ++i) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    
    int cnt = 0;
    for (int x = 1; x <= n; ++x) {
        bool v = true;
        for (int ne : adj[x]) {
            if (color[ne] == color[x]) {
                v = false;
                break;
            }
        }
        if (v) {
            cnt++;
        }
    }
    cout << cnt << endl;
    return 0;
}