Submission #79820

#	Time	Username	Problem	Language	Result	Execution time	Memory
79820		Pajaraja	Hard route (IZhO17_road)	C++17	52 / 100	551 ms	29532 KiB

road

#include <bits/stdc++.h>
#define MAXN 500000
using namespace std;
vector<int> g[MAXN];
int d[MAXN];
long long pot,cnt;
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);
}
int dfsp(int s,int f)
{
	int mx=0;
	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;
	return mx+1;
}
void calc(int s,int f,long long mx,long long du)
{
	if(s!=f && g[s].size()==1)
	{
		if(du*mx==pot) cnt++;
		if(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);
}
int main()
{
	int n,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;
	for(int i=1;i<=n;i++) if(g[i].size()==1)
	{
		dfsp(i,i);
		calc(i,i,0,0);
	}
	printf("%lld %lld",pot,cnt/2);
}

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 'int dfsp(int, 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) mx=max(mx,dfsp(g[s][i],s));
              ~^~~~~~~~~~~~
road.cpp: In function 'void calc(int, int, long long int, long long int)':
road.cpp:29:15: 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:30:15: 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:32:15: 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 'int main()':
road.cpp:37:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
road.cpp:41:8: 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: 0 / 48