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| #include <bits/stdc++.h>
using namespace std;
const int MAXN = 3e5 + 5;
int n;
int a[MAXN], id[MAXN];
vector<int> G[MAXN];
set<int> s[MAXN];
int ans = 0;
void dfs(int u, int fa) {
int lst = 0;
for (vector<int>::iterator it = G[u].begin(); it != G[u].end(); it++) {
int v = *it;
if (v == fa) continue;
dfs(v, u);
if (lst) {
if (s[id[lst]].size() > s[id[v]].size()) swap(id[lst], id[v]);
int t = s[id[lst]].size();
for (set<int>::iterator it = s[id[lst]].begin(); it != s[id[lst]].end(); it++)
s[id[v]].insert(*it);
}
lst = v;
}
if (lst) {
set<int>::iterator it = s[id[lst]].lower_bound(a[u]);
if (it == s[id[lst]].begin()) {
s[id[lst]].insert(a[u]);
} else {
it--;
s[id[lst]].erase(it);
s[id[lst]].insert(a[u]);
}
swap(id[lst], id[u]);
} else {
s[id[u]].insert(a[u]);
}
int t = s[id[u]].size();
ans = max(ans, (int)s[id[u]].size());
}
int main() {
freopen("choice.in", "r", stdin);
freopen("choice.out", "w", stdout);
scanf("%d", &n);
for (int i = 1; i <= n; ++i) scanf("%d", &a[i]), id[i] = i;
for (int i = 1; i < n; ++i) {
int u, v;
scanf("%d%d", &u, &v);
G[u].push_back(v), G[v].push_back(u);
}
dfs(1, 0);
printf("%d", ans);
return 0;
}
|