Submission #79840

#	Time	Username	Problem	Language	Result	Execution time	Memory
79840		Pajaraja	Hard route (IZhO17_road)	C++17	100 / 100	1951 ms	172468 KiB

road

#include <bits/stdc++.h>
#define MAXN 500007
using namespace std;
vector<int> g[MAXN];
int b,mb,u,v,in[MAXN],out[MAXN],c1,c2,n,p[MAXN];
long long pot,cnt,d[MAXN],k[MAXN],ds[2][MAXN];
void dfsD(int s,int f,int di)
{
	d[s]=di;
	for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) dfsD(g[s][i],s,di+1);
}
void dfsd(int s,int f,int ka,long long di)
{
	ds[ka][s]=di;
	for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) dfsd(g[s][i],s,ka,di+1);
}
int dfsp(int s,int f)
{
	int mx=0;
	in[c1++]=s;
	p[s]=f;
	for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) mx=max(mx,dfsp(g[s][i],s));
	d[s]=mx+1;
	out[c2++]=s;
	return d[s];
}
void calc(int s,int f,long long mx,long long du)
{
	if(s!=f && g[s].size()==1)
	{
		if(s!=mb && du*mx==pot) cnt++;
		if(s!=mb && du*mx>pot) {pot=du*mx; cnt=1;}
		return;
	}
	int mxi=0;
	long long mx1=0,mx2=0;
	for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]>mx1) {mx1=d[g[s][i]]; mxi=i;}
	for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(i!=mxi) mx2=max(mx2,(long long)d[g[s][i]]);
	calc(g[s][mxi],s,max(mx,mx2),du+1);
	for(int i=0;i<g[s].size();i++) if(g[s][i]!=f && i!=mxi) calc(g[s][i],s,max(mx,mx1),du+1);
}
inline void dfs(int ka)
{
	for(int i=0;i<n;i++)
	{
		int s=out[i],f=p[s];
		long long du=ds[ka][s];
		if(s==v || s==u) {d[s]=-MAXN; continue;}
		if(g[s].size()==1) {k[s]=1; d[s]=1; continue;}
		int mxi=0;
		long long mx1=0,mx2=0;
		k[s]=0;
		for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]>mx1) {mx1=d[g[s][i]]; mxi=i;}
		for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]==mx1) k[s]+=k[g[s][i]];
		for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(i!=mxi) mx2=max(mx2,(long long)d[g[s][i]]);
		d[s]=mx1+1;
		long long tc=0;
		if(mx1==mx2)
		{
			tc=k[s]*k[s];
			for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]==mx1) tc-=k[g[s][i]]*k[g[s][i]];
			tc/=2;
		}
		else
		{
			for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]==mx2) tc+=k[g[s][i]];
			tc*=k[s];
		}
		if(mx2==0 || (ka==1 && ds[0][s]==ds[1][s])) continue;
		if((mx1+mx2)*du>pot) {pot=(mx1+mx2)*du; cnt=0;}
		if((mx1+mx2)*du==pot) cnt+=tc;
	}
}
int main()
{
	u=1; v=1;
	scanf("%d",&n);
	for(int i=0;i<n-1;i++)
	{
		int t1,t2;
		scanf("%d%d",&t1,&t2);
		g[t1].push_back(t2);
		g[t2].push_back(t1);
	}
	dfsD(1,1,0);
	for(int i=1;i<=n;i++) if(d[i]>d[u]) u=i;
	dfsD(u,u,0);
	for(int i=1;i<=n;i++) if(d[i]>d[v]) v=i;
	dfsd(u,u,0,0);
	dfsd(v,v,1,0);
	dfsp(u,u);
	calc(u,u,0,0);
	dfs(0);
	mb=u; c1=0; c2=0;
	dfsp(v,v);
	calc(v,v,0,0);
	dfs(1);
	printf("%lld %lld",pot,cnt);
}

Compilation message (stderr)

road.cpp: In function 'void dfsD(int, int, int)':
road.cpp:10:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) dfsD(g[s][i],s,di+1);
              ~^~~~~~~~~~~~
road.cpp: In function 'void dfsd(int, int, int, long long int)':
road.cpp:15:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) dfsd(g[s][i],s,ka,di+1);
              ~^~~~~~~~~~~~
road.cpp: In function 'int dfsp(int, int)':
road.cpp:22:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) mx=max(mx,dfsp(g[s][i],s));
              ~^~~~~~~~~~~~
road.cpp: In function 'void calc(int, int, long long int, long long int)':
road.cpp:37:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]>mx1) {mx1=d[g[s][i]]; mxi=i;}
              ~^~~~~~~~~~~~
road.cpp:38:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(i!=mxi) mx2=max(mx2,(long long)d[g[s][i]]);
              ~^~~~~~~~~~~~
road.cpp:40:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[s].size();i++) if(g[s][i]!=f && i!=mxi) calc(g[s][i],s,max(mx,mx1),du+1);
              ~^~~~~~~~~~~~
road.cpp: In function 'void dfs(int)':
road.cpp:53:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]>mx1) {mx1=d[g[s][i]]; mxi=i;}
               ~^~~~~~~~~~~~
road.cpp:54:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]==mx1) k[s]+=k[g[s][i]];
               ~^~~~~~~~~~~~
road.cpp:55:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(i!=mxi) mx2=max(mx2,(long long)d[g[s][i]]);
               ~^~~~~~~~~~~~
road.cpp:61:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]==mx1) tc-=k[g[s][i]]*k[g[s][i]];
                ~^~~~~~~~~~~~
road.cpp:66:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0;i<g[s].size();i++) if(g[s][i]!=f) if(d[g[s][i]]==mx2) tc+=k[g[s][i]];
                ~^~~~~~~~~~~~
road.cpp: In function 'int main()':
road.cpp:77:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
road.cpp:81:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&t1,&t2);
   ~~~~~^~~~~~~~~~~~~~~~

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