Submission #1127190

#	Time	Username	Problem	Language	Result	Execution time	Memory
1127190		bekzhan29	Hard route (IZhO17_road)	C++20	52 / 100	2099 ms	51484 KiB

road

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define INF (long long)(2e15)
#define mod2 998244353
#define mod 1000000007
#define eps 1e-9
#define abs(x) ((x)>=0?(x):-(x))
#define y1 solai
#define fi first
#define se second
typedef int ll;
typedef long double ld;
typedef pair<ll,ll> pll;
typedef pair<double,double> pdd;
typedef pair<pll, ll> plll;
mt19937 rng(29);
const ll N=500100;
ll n,x,y,ans,cnt=1,d[N],c[N];
vector<ll>v[N];
void dfs(ll x, ll pr=0)
{
	d[x]=1;
	c[x]=1;
	for(ll to:v[x])
	{
		if(to==pr)
			continue;
		dfs(to,x);
		if(d[to]+1>d[x])
		{
			d[x]=d[to]+1;
			c[x]=c[to];
		}
		else if(d[to]+1==d[x])
			c[x]+=c[to];
	}
}
bool cmp(ll a, ll b)
{
	return d[a]>d[b];
}
void solve(ll x)
{
	dfs(x);
	sort(v[x].begin(),v[x].end(),&cmp);
	for(ll j=0;j<v[x].size();j++)
		for(ll k=j+1;k<v[x].size();k++)
			for(ll i=0;i<v[x].size();i++)
			{
				if(i==j||i==k)
					continue;
				ll a=v[x][i],b=v[x][j],cc=v[x][k];
				if(d[a]*(d[b]+d[cc])==ans)
				{
					cnt+=c[b]*c[cc];
					break;
				}
				else if(d[a]*(d[b]+d[cc])>ans)
				{
					ans=d[a]*(d[b]+d[cc]);
					cnt=c[b]*c[cc];
					break;
				}
			}
}
int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	cin>>n;
	for(ll i=1;i<n;i++)
		cin>>x>>y,v[x].pb(y),v[y].pb(x);
	for(ll i=1;i<=n;i++)
		if(v[i].size()>2)
			solve(i);
	cout<<ans<<" "<<cnt<<endl;
}
/*
7
1 2
1 3
2 4
2 5
3 6
3 7

4
1 2
2 3
2 4

5
1 2
2 3
3 4
4 5

*/

• Subtask 1: 19 / 19
• Subtask 2: 33 / 33
• Subtask 3: 0 / 48