#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5 + 7;
vector<pair<int, int>> g[N];
int ans = 0;
vector<ll> find_dist(int n, int x) {
vector<ll> dist(n, -1);
queue<int> q;
q.push(x);
dist[x] = 0;
while (!q.empty()) {
int u = q.front();
q.pop();
for (auto v : g[u]) {
if (dist[v.first] == -1) {
dist[v.first] = dist[u] + v.second;
q.push(v.first);
}
}
}
return dist;
}
int max_score(int n, int X, int Y, ll K, vector<int> U, vector<int> V, vector<int> W) {
for (int i = 0; i < n; ++i) {
g[i].clear();
}
ans = 0;
for (int i = 0; i < n - 1; ++i) {
g[U[i]].push_back(make_pair(V[i], W[i]));
g[V[i]].push_back(make_pair(U[i], W[i]));
}
vector<ll> distX = find_dist(n, X);
vector<ll> distY = find_dist(n, Y);
vector<ll> one(n, 0), two(n, 0);
for (int i = 0; i < n; ++i) {
one[i] = min(distX[i], distY[i]);
two[i] = max(distX[i], distY[i]);
}
{ // we take only ones
vector<ll> aux = one;
sort(aux.begin(), aux.end());
ll sum = 0;
for (int i = 0; i < n; ++i) {
if (sum + aux[i] <= K) {
ans++;
sum += aux[i];
}
}
}
// we take some twos => we take all twos on path X-Y
vector<bool> counted(n, 0);
ll d = distX[Y], between = 0;
int cnt = 0;
for (int i = 0; i < n; ++i) {
if (distX[i] + distY[i] == d && i != X && i != Y) {
between += two[i];
cnt++;
counted[i] = 1;
}
}
ll sum_other_two = 0;
vector<int> ord2(n);
iota(ord2.begin(), ord2.end(), 0);
sort(ord2.begin(), ord2.end(), [&](int x, int y) {
return two[x] < two[y];
});
int ptr = 0;
vector<int> ord1(n);
iota(ord1.begin(), ord1.end(), 0);
sort(ord1.begin(), ord1.end(), [&](int x, int y) {
return one[x] < one[y];
});
auto get_sum_other_one = [&](int twos, int ones) {
ll sum = 0;
for (int i = 0; i < n; ++i) {
if (counted[ord1[i]] == 0) {
sum += one[ord1[i]];
ones--;
if (ones == 0) {
break;
}
}
}
return sum;
};
for (int twos = 0; twos + cnt <= n; ++twos) {
if (twos != 0) {
while (ptr < n && counted[ord2[ptr]] == 1) {
ptr++;
}
sum_other_two += two[ord2[ptr]];
counted[ord2[ptr]] = 1;
}
for (int ones = 0; ones + twos + cnt <= n; ones++) {
if (sum_other_two + between + get_sum_other_one(twos, ones) <= K) {
ans = max(ans, 2 * (twos + cnt) + ones);
}
}
}
return ans;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int t;
cin >> t;
while (t--) {
int N, X, Y, K;
cin >> N >> X >> Y >> K;
vector<int> U(N - 1, 0), V(N - 1, 0), W(N - 1, 0);
for (int i = 0; i < N - 1; ++i) {
cin >> U[i] >> V[i] >> W[i];
}
cout << max_score(N, X, Y, K, U, V, W) << "\n";
}
return 0;
}
Compilation message
/usr/bin/ld: /tmp/cczCnDNx.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccFdla1w.o:closing.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status
