| # | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 960814 | 2024-04-11T05:00:03 Z | Trisanu_Das | Hard route (IZhO17_road) | C++17 | 0 ms | 0 KB |
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ff first
#define ss second
int n, dp[500005], cnt[500005], res = 0, way = 1;
vector<int> adj[500005];
void init(int u, int p){
cnt[u] = 1;
for (auto x : adj[u]){
if (x == p) continue;
init(x, u);
if (dp[x] + 1 == dp[u]) cnt[u] += cnt[x];
if (dp[x] + 1 > dp[u]) cnt[u] = cnt[x];
dp[u] = max(dp[u], dp[x] + 1);
}
}
bool cmp (int& i, int& j){
return dp[i] > dp[j];
}
void rr(int u, int p){
sort(adj[u].begin(), adj[u].end(), cmp);
if (adj[u].size() >= 3){
int cur = 0, cn = 0;
int a = dp[adj[u][0]] + 1, b = dp[adj[u][1]] + 1, c = dp[adj[u][2]] + 1;
cur = a * (b + c);
int ca = 0;
for (auto x : adj[u]){
if (dp[x] + 1 == c) cn += ca * cnt[x];
if (dp[x] + 1 == b) ca += cnt[x];
}
if (cur > res) res = cur, way = cn;
else if (cur == res) way += cn;
}
ii f = {0, 1}, s = {0, 0};
for (auto x : adj[u]){
if (dp[x] + 1 > f.ff) s = f, f = {dp[x] + 1, cnt[x]};
else if (dp[x] + 1 == f.ff) f.ss += cnt[x];
else if (dp[x] + 1 > s.ff) s = {dp[x] + 1, cnt[x]};
else if (dp[x] + 1 == s.ff) s.ss += cnt[x];
}
int tmpdp = dp[u], tmpcnt = cnt[u];
for (auto x : adj[u]){
if (x == p) continue;
dp[u] = f.ff, cnt[u] = f.ss;
if (dp[x] + 1 == f.ff && cnt[x] == f.ss) dp[u] = s.ff, cnt[u] = s.ss;
else if (dp[x] + 1 == f.ff && cnt[x] != f.ss) dp[u] = f.ff, cnt[u] = f.ss - cnt[x];
rr(x, u);
}
dp[u] = tmpdp, cnt[u] = tmpcnt;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cin >> n;
for (int i = 1; i < n; i++){
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
init(1, 0);
rr(1, 0);
cout << res << ' ' << way;
}