Submission #1038295

#	Time	Username	Problem	Language	Result	Execution time	Memory
1038295		MMihalev	Hard route (IZhO17_road)	C++14	19 / 100	163 ms	42844 KiB

road

#include<iostream>
#include<algorithm>
#include<iomanip>
#include<cmath>
#include<cstring>
#include<vector>
#include<queue>
#include<stack>
#include<tuple>
#include<set>
#include<map>
#include<random>
#include<chrono>
using namespace std;
const int MAX_N=5e5+5;
int maxd[MAX_N];
int maxd2[MAX_N];
int dp[MAX_N];
vector<int>g[MAX_N];
int n;
int cnt[MAX_N];
int depth[MAX_N];
int ans;
void dfsdown(int u,int par)
{
    for(int v:g[u])
    {
        if(v==par)continue;
        depth[v]=depth[u]+1;
        dfsdown(v,u);
        if(maxd[v]+1>maxd[u])
        {
            maxd2[u]=maxd[u];
            maxd[u]=maxd[v]+1;
        }
        else if(maxd[v]+1==maxd[u])
        {
            maxd2[u]=maxd[u];
        }
    }
}
void dfsup(int u,int par)
{
    for(int v:g[u])
    {
        if(v==par)continue;

        int cur=maxd[u];
        if(maxd[v]+1==maxd[u])cur=maxd2[u];

        dp[v]=max(dp[u],cur);

        dfsup(v,u);
    }
}
void solvefor(int root)
{
    for(int i=1;i<=n;i++)
    {
        maxd[i]=0;
        maxd2[i]=0;
        dp[i]=0;
        depth[i]=0;
    }
    dfsdown(root,0);
    dfsup(root,0);
    for(int i=1;i<=n;i++)
    {
        if(g[i].size()!=1 or i==root)continue;
        int curhardness=depth[i]*dp[i];
        cnt[curhardness]++;
        ans=max(ans,curhardness);
    }
}
signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);

    cin>>n;
    for(int i=1;i<n;i++)
    {
        int u,v;
        cin>>u>>v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    for(int i=1;i<=n;i++)
    {
        if(g[i].size()!=1)continue;
        solvefor(i);
    }
    cout<<ans<<" "<<cnt[ans]/2<<"\n";
    return 0;
}

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