2025-09-12 14:50:25 -03:00

129 lines
2.4 KiB
C++

/* Problem URL: https://codeforces.com/problemset/problem/580/C */
#include <bits/stdc++.h>
using namespace std;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (size_t i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (size_t i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
V<bool> cat(n);
rep(i, n) {
bool c;
cin >> c;
cat[i] = c;
}
vvi graph(n);
nrep(i, 1, n) {
int a, b;
cin >> a >> b;
a--, b--;
graph[a].push_back(b);
graph[b].push_back(a);
}
function<int(int, int, int)> dfs = [&](int i, int p, int c){
if (cat[i]) {
c++;
} else {
c = 0;
}
if (c > m) {
return 0;
}
if (graph[i].size() == 1 && graph[i][0] == p) {
return 1;
}
int ans = 0;
for (auto j : graph[i]) {
if (j == p) {
continue;
}
ans += dfs(j, i, c);
}
return ans;
};
cout << dfs(0, 0, 0) << '\n';
}