Submission #962331

#	Time	Username	Problem	Language	Result	Execution time	Memory
962331		Cookie	Hard route (IZhO17_road)	C++14	0 / 100	4 ms	20044 KiB

road

#include<bits/stdc++.h>
#include<fstream>
using namespace std;
#define sz(a) (int)a.size()
#define ALL(v) v.begin(), v.end()
#define ALLR(v) v.rbegin(), v.rend()
#define ll long long
#define pb push_back
#define forr(i, a, b) for(int i = a; i < b; i++)
#define dorr(i, a, b) for(int i = a; i >= b; i--)
#define ld long double
#define vt vector
#include<fstream>
#define fi first
#define se second
#define pll pair<ll, ll>
#define pii pair<int, int>
#define mpp make_pair
const ld PI = 3.14159265359, prec = 1e-9;;
//using u128 = __uint128_t;
//const int x[4] = {1, 0, -1, 0};
//const int y[4] = {0, -1, 0, 1};
const ll mod = 1e9 + 7, pr = 31;
const int mxn = 5e5 + 5, mxq = 1e5 + 5, sq = 450, mxv = 5e4 + 1;
//const int base = (1 <<18);
const ll inf = 1e9 + 5, neg = -69420, inf2 = 1e14;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
// have fun!
struct DP{
    ll mx, cnt;
    DP(){
        mx = 0; cnt = 1;
    }
    DP(ll _mx, ll _cnt){
        mx = _mx; cnt = _cnt;
    }
};
DP comb(DP a, DP b){
    if(a.mx > b.mx)return(a);
    if(a.mx < b.mx)return(b);
    return(DP(a.mx, a.cnt + b.cnt));
}
int n;
DP dp[mxn + 1];
vt<int>adj[mxn + 1];
void dfs(int s, int pre){
    for(auto i: adj[s]){
        if(i != pre){
            dfs(i, s);
            dp[s] = comb(dp[s], DP(dp[i].mx + 1, dp[i].cnt));
        }
    }
    
}
DP res;
bool cmp(int a, int b){
    return(dp[a].mx > dp[b].mx);
}
void dfs2(int s, int pre){
    sort(ALL(adj[s]), cmp);
    if(sz(adj[s]) >= 3){
        ll mx0 = dp[adj[s][0]].mx + 1, mx1 = dp[adj[s][1]].mx + 1, mx2 = dp[adj[s][2]].mx + 1;
        ll pref = 0;
        DP cand = DP(mx0 * (mx1 + mx2), 0);
        for(auto i: adj[s]){
            if(dp[i].mx + 1 == mx1)cand.cnt += pref * dp[i].cnt;
            if(dp[i].mx + 1 == mx2)pref += dp[i].cnt;
        }
        res = comb(res, cand);
    }
    DP fir, sec;
    for(auto i: adj[s]){
        if(dp[i].mx + 1 > fir.mx){
            sec = fir;
            fir = DP(dp[i].mx + 1, dp[i].cnt);
        }
        else if(dp[i].mx + 1 == fir.mx)fir.cnt += dp[i].cnt;
        else if(dp[i].mx + 1 > sec.mx)sec = DP(dp[i].mx + 1, dp[i].cnt);
        else if(dp[i].mx + 1 == sec.mx)sec.cnt += dp[i].cnt;
    }
    DP rem = dp[s];
    for(auto i: adj[s]){
        if(i != pre){
            dp[s] = fir;
            if(dp[s].mx == dp[i].mx + 1){
                if(dp[s].cnt == dp[i].cnt){
                    dp[s] = sec;
                }else{
                    dp[s].cnt -= dp[i].cnt;
                }
            }
            dfs2(i, s);
        }
    }
    dp[s] = rem;
}
void solve(){
    cin >> n;
    for(int i = 1; i < n; i++){
        int u, v; cin >> u >> v;
        adj[u].pb(v); adj[v].pb(u); 
    }
    dfs(1, -1); dfs2(1, -1);
    cout << res.mx << " " << res.cnt;
}
signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    //freopen("netw.inp", "r", stdin);
    //freopen("netw.out", "w", stdout)
    int tt; tt = 1;
    while(tt--){
        solve();
 
    }
    return(0);
}

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