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| #include <bits/stdc++.h>
using namespace std;
using LL = long long;
#define FOR(i, x, y) for (decay<decltype(y)>::type i = (x), _##i = (y); i < _##i; ++i)
#define FORD(i, x, y) for (decay<decltype(x)>::type i = (x), _##i = (y); i > _##i; --i)
#ifdef zerol
#define dbg(args...) do { cout << "\033[32;1m" << #args << " -> "; err(args); } while (0)
#else
#define dbg(...)
#endif
void err() { cout << "\033[39;0m" << endl; }
template<template<typename...> class T, typename t, typename... Args>
void err(T<t> a, Args... args) { for (auto x: a) cout << x << ' '; err(args...); }
template<typename T, typename... Args>
void err(T a, Args... args) { cout << a << ' '; err(args...); }
// -----------------------------------------------------------------------------
const int maxn = 2E5 + 100, INF = 2E9 + 3;
int w[maxn];
struct E {
int to, c;
};
vector<E> G[maxn];
int n, m, L, R, ans = -INF;
namespace tree {
#define mid ((l + r) >> 1)
#define lson l, mid
#define rson mid + 1, r
extern struct P *null, *pit;
struct P {
int max;
P *ls, *rs;
} *null = new P {-INF, nullptr, nullptr}, pool[maxn * 20], *pit = pool;
P* ins(P* t, int p, int v, int l = 1, int r = n) {
if (p < l || r < p) return t;
if (t == null) t = new (pit++) P{-INF, null, null};
t->max = max(t->max, v);
if (l != r) {
t->ls = ins(t->ls, p, v, lson);
t->rs = ins(t->rs, p, v, rson);
}
return t;
}
int query(P* t, int ql, int qr, int l = 1, int r = n) {
if (t == null || qr < l || r < ql) return -INF;
if (ql <= l && r <= qr) return t->max;
return max(query(t->ls, ql, qr, lson), query(t->rs, ql, qr, rson));
}
P* merge(P* a, P* b) {
if (a == null) return b; if (b == null) return a;
a->max = max(a->max, b->max);
a->ls = merge(a->ls, b->ls); a->rs = merge(a->rs, b->rs);
return a;
}
inline void clear() { pit = pool; }
}
int sz[maxn];
bool vis[maxn];
int get_sz(int u, int fa) {
int& s = sz[u] = 1;
for (E& e: G[u]) {
int v = e.to;
if (vis[v] || v == fa) continue;
s += get_sz(v, u);
}
return s;
}
void get_rt(int u, int fa, int s, int& m, int& rt) {
int t = s - sz[u];
for (E& e: G[u]) {
int v = e.to;
if (vis[v] || v == fa) continue;
get_rt(v, u, s, m, rt);
t = max(t, sz[v]);
}
if (t < m) { m = t; rt = u; }
}
void solve(void f(int)) {
static stack<int> S;
S.push(1);
while (!S.empty()) {
int u = S.top(); S.pop();
int tmp = INF; get_rt(u, -1, get_sz(u, -1), tmp, u);
vis[u] = true;
f(u);
for (E& e: G[u]) {
int v = e.to;
if (vis[v]) continue;
S.push(v);
}
}
}
void fuck(int u) {
using namespace tree;
sort(G[u].begin(), G[u].end(), [](const E& a, const E& b) { return a.c < b.c; });
clear();
P *rt = null, *cur = null;
int last_c = -1;
static vector<pair<int, int>> X;
function<void(int, int, int, int, int)> go =
[&](int u, int fa, int d, int last_c, int val) {
if (d > R) return;
X.emplace_back(d, val);
for (E& e: G[u]) {
int v = e.to;
if (v == fa || vis[v]) continue;
go(v, u, d + 1, e.c, val + (e.c == last_c ? 0 : w[e.c]));
}
};
for (E& e: G[u]) {
X.clear();
int v = e.to;
if (vis[v]) continue;
if (e.c != last_c) { rt = merge(rt, cur); cur = null; last_c = e.c; }
go(v, -1, 1, e.c, w[e.c]);
for (auto& x: X) {
int d = x.first, val = x.second;
if (d > R) continue;
if (d >= L) ans = max(ans, val);
ans = max(ans, query(rt, L - d, R - d) + val);
ans = max(ans, query(cur, L - d, R - d) + val - w[e.c]);
}
for (auto& x: X)
if (x.first <= R)
cur = ins(cur, x.first, x.second);
}
}
int main() {
#ifdef zerol
freopen("journey2.in", "r", stdin);
#endif
cin >> n >> m >> L >> R;
FOR (i, 1, m + 1) scanf("%d", &w[i]);
FOR (_, 1, n) {
int u, v, c; scanf("%d%d%d", &u, &v, &c);
G[u].push_back({v, c}); G[v].push_back({u, c});
}
solve(fuck);
cout << ans << endl;
}
|