Submission #913965

#	Time	Username	Problem	Language	Result	Execution time	Memory
913965		MilosMilutinovic	Hard route (IZhO17_road)	C++14	52 / 100	803 ms	262144 KiB

road

#include<bits/stdc++.h>
 
#define pb push_back
#define fi first
#define se second
#define mp make_pair
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef long double ld;
 
template <typename T> bool chkmin(T &x,T y){return x>y?x=y,1:0;}
template <typename T> bool chkmax(T &x,T y){return x<y?x=y,1:0;}
 
ll readint(){
	ll x=0,f=1; char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
	return x*f;
}
 
int n,tot;
int mx[500005],cnt[500005];
vector<int> g[500005];
ll res=0,c=1;
vector<pii> f;
 
void addedge(int x,int y){ g[x].pb(y); g[y].pb(x); }
 
void dfs(int x,int px,int d){
	mx[x]=d;
	cnt[x]=1;
	for(auto&v:g[x]){
		if(v==px) continue;
		dfs(v,x,d+1);
		if(mx[v]==mx[x]) cnt[x]+=cnt[v];
		else if(mx[x]<mx[v]) cnt[x]=cnt[v];
		mx[x]=max(mx[x],mx[v]);
	}
}
 
void reroot(int x,int px,int d){
	f.clear();
	for(auto&v:g[x]){
		if(v!=px) mx[v]-=d;
		f.pb(mp(mx[v],cnt[v]));
	}
	sort(f.rbegin(),f.rend());
	if((int)f.size()>=3){
		ll cur=0,cc=0;
		cur=f[0].fi*1ll*(f[1].fi+f[2].fi);
		ll s=0;
		for(int j=0;j<f.size();j++){
			if(f[j].fi==f[2].fi) cc+=s*f[j].se;
			if(f[j].fi==f[1].fi) s+=f[j].se;
		}
		if(res<cur) res=cur,c=cc;
		else if(res==cur) c+=cc;
	}
	int mx_bef=mx[x],cnt_bef=cnt[x];
	multiset<int> st;
	map<int,int> m;
	for(auto&v:g[x]){
		st.insert(mx[v]);
		m[mx[v]]+=cnt[v];
	}
	st.insert(0);
	m[0]+=1;
	for(auto&v:g[x]){
		if(v==px) continue;
		st.erase(st.find(mx[v]));
		m[mx[v]]-=cnt[v];
		mx[x]=*prev(st.end())+1;
		cnt[x]=m[mx[x]-1];
		reroot(v,x,d+1);
		st.emplace(mx[v]);
		m[mx[v]]+=cnt[v];
	}
	mx[x]=mx_bef;
	cnt[x]=cnt_bef;
}
 
int main(){
	n=readint();
	for(int i=1;i<n;i++) addedge(readint(),readint());
	dfs(1,1,0);
	reroot(1,1,0);
	printf("%lld %lld\n",res,c);
	return 0;
}

Compilation message (stderr)

road.cpp: In function 'void reroot(int, int, int)':
road.cpp:57:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |   for(int j=0;j<f.size();j++){
      |               ~^~~~~~~~~

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