Submission #706845

#	Time	Username	Problem	Language	Result	Execution time	Memory
706845		bLIC	Hard route (IZhO17_road)	C++17	0 / 100	8 ms	12064 KiB

road

/**
 *  Author: Anil Byar
**/

#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>

// using namespace __gnu_pbds;
using namespace std;

// template<class T>
// using ordered_set = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;



#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)(x).size()
#define ft first
#define sd second
#define pb push_back

// Source: https://codeforces.com/blog/entry/68809
// { start
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '"' << x << '"';}
void __print(const string &x) {cerr << '"' << x << '"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
// } end


typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vii;
typedef vector<ll> vl;
typedef vector<pll> vll;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
typedef vector<vl> vvl;

#define dbg if(0)

const ll MOD = 1e9+7;
const ll MOD9 = 998244353;
const ll INFLL = 1e18+5;
const int INF = 1e9;
const int maxN = 500005;
const int maxK = 8001;

void printbit(int x, int len) {string s="\n";while(len--){s=((x%2)?'1':'0')+s;x/=2;} cout<<s;}
ll power(ll x, ll y, ll mod){if (y==0) return 1;ll ret = power(x, y/2, mod);ret *= ret;ret%=mod;if (y&1) ret *= x;return ret%mod;}
ll modinv(ll x, ll mod) {return power(x, mod-2, mod);}

template<class T>
istream& operator>>(istream&in, vector<T>&v){
    for (T& x:v) in>>x;
    return in;
}
template<class T>
ostream& operator<<(ostream&out, vector<T>&v){
    for (T& x:v) out<<x<<' ';
    cout<<'\n';
    return out;
}

int n;
vi adj[maxN];
ll dpup[maxN], dpdown[maxN];


void dfs1(int node, int par){
    dpdown[node] = 0;
    for (int x:adj[node]){
        if (x==par) continue;
        dfs1(x, node);
        dpdown[node] = max(dpdown[node], dpdown[x]+1);
    }
}

void dfs2(int node, int par){
    int m = sz(adj[node]);
    ll prefmax[m+1];
    prefmax[0] = 0;
    for (int i = 0;i<m;i++){
        int x = adj[node][i];
        prefmax[i+1] = prefmax[i];
        if (x==par) continue;
        prefmax[i+1] = max(prefmax[i+1], dpdown[x]+2);
    }
    ll mx = 0;
    for (int i = m-1;i>=0;i--){
        int x = adj[node][i];
        if (x==par) continue;
        dpup[x] = max(dpup[node]+1, max(mx, prefmax[i]));
        mx = max(mx, dpdown[x]+2);
        // cout<<x<<" up "<<dpup[x]<<endl;
        dfs2(x, node);
    }
}


ll val, cont;

void dfs(int node, int par){
    vl dist = {0, 0, dpup[node]};
    for (int x:adj[node]){
        if (x==par) continue;
        dist.push_back(dpdown[x] + 1);
        dfs(x, node);
    }
    sort(rall(dist));
    ll ans = dist[0]*(dist[2]+dist[1]);
    ll possinc = 0;
    ll c = count(all(dist), dist[2]);
    if (dist[1]==dist[2]) possinc = (c*(c-1))/2;
    else possinc = c;

    if (ans>val){
        val = ans;
        cont = possinc;
    } else if (ans==val) cont+=possinc;
}

void solve(){
    cin>>n;
    for (int i = 0;i<n-1;i++){
        int u, v;cin>>u>>v;
        adj[u].pb(v);
        adj[v].pb(u);
    }
    int ct = 0;
    for (int i= 1;i<=n;i++){
        ct = max(ct, sz(adj[i]));
    }
    if (ct<=2){
        cout<<"0 1";
        return;
    }
    dfs1(1, -1);
    dfs2(1, -1);
    dfs(1, -1);
    cout<<val<<" "<<cont;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

// #define _DEBUG
#ifdef _DEBUG
    freopen("input.in", "r", stdin);
    freopen("output.out", "w", stdout);
    int tt = clock();
#endif

    int t=1, i = 1;
    // cin>>t;
    while(t--){
        // cout<<"Case #"<<i++<<": ";
        solve();
        cout<<'\n';
    }
#ifdef _DEBUG
    cerr << "TIME = " << (float)(clock() - tt)/CLOCKS_PER_SEC << endl;
    tt = clock();
#endif
}

Compilation message (stderr)

road.cpp: In function 'int main()':
road.cpp:182:14: warning: unused variable 'i' [-Wunused-variable]
  182 |     int t=1, i = 1;
      |              ^

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