175 lines
3.2 KiB
C++
175 lines
3.2 KiB
C++
/* Problem URL: https://codeforces.com/problemset/problem/1822/F */
|
|
|
|
#include <bits/stdc++.h>
|
|
#include <ext/pb_ds/assoc_container.hpp>
|
|
#include <ext/pb_ds/tree_policy.hpp>
|
|
|
|
using namespace std;
|
|
using namespace __gnu_pbds;
|
|
|
|
template <class T, class comp = less<>>
|
|
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
|
|
|
|
#define V vector
|
|
|
|
#define rmin(a, b) a = min(a, b)
|
|
#define rmax(a, b) a = max(a, b)
|
|
|
|
#define rep(i, lim) for (int i = 0; i < (lim); i++)
|
|
#define nrep(i, s, lim) for (int 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;
|
|
}
|
|
|
|
const int oo = INT32_MAX >> 1;
|
|
const ll OO = INT64_MAX >> 1;
|
|
|
|
|
|
void pre()
|
|
{
|
|
|
|
}
|
|
|
|
#define TEST 1
|
|
|
|
void solve()
|
|
{
|
|
int n;
|
|
cin >> n;
|
|
ll k, c;
|
|
cin >> k >> c;
|
|
|
|
vvi graph(n);
|
|
rep(i, n - 1) {
|
|
int a, b;
|
|
cin >> a >> b;
|
|
a--, b--;
|
|
graph[a].push_back(b);
|
|
graph[b].push_back(a);
|
|
}
|
|
|
|
vi dis(n);
|
|
vi dp(n);
|
|
dis[0] = -1;
|
|
|
|
function<int(int, int)> dfs = [&](int i, int p) {
|
|
dis[i] = dis[p] + 1;
|
|
repv(j, graph[i]) {
|
|
if (j == p) {
|
|
continue;
|
|
}
|
|
|
|
rmax(dp[i], dfs(j, i) + 1);
|
|
}
|
|
|
|
return dp[i];
|
|
};
|
|
|
|
dfs(0, 0);
|
|
|
|
function<void(int, int)> reroot = [&](int i, int p) {
|
|
ll c1 = -1;
|
|
ll c2 = -1;
|
|
repv(j, graph[i]) {
|
|
if (dp[j] + 1 > c1) {
|
|
c2 = c1;
|
|
c1 = dp[j] + 1;
|
|
continue;
|
|
}
|
|
|
|
if (dp[j] + 1 > c2) {
|
|
c2 = dp[j] + 1;
|
|
}
|
|
}
|
|
|
|
ll ans = c1;
|
|
|
|
repv(j, graph[i]) {
|
|
if (j == p) {
|
|
continue;
|
|
}
|
|
dp[i] = dp[j] + 1 == ans ? c2 : c1;
|
|
reroot(j, i);
|
|
}
|
|
|
|
dp[i] = ans;
|
|
};
|
|
|
|
reroot(0, 0);
|
|
|
|
ll ans = 0;
|
|
rep(i, n) {
|
|
rmax(ans, dp[i] * k - dis[i] * c);
|
|
}
|
|
|
|
cout << ans << '\n';
|
|
}
|
|
|
|
int main()
|
|
{
|
|
ios::sync_with_stdio(false);
|
|
cin.tie(nullptr);
|
|
|
|
pre();
|
|
|
|
int t;
|
|
(TEST && cin >> t) || (t = 1);
|
|
while (t--) {
|
|
solve();
|
|
}
|
|
}
|