제출 #1130316

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1130316		brover29	Hard route (IZhO17_road)	C++20	0 / 100	4 ms	5192 KiB

road

#include <bits/stdc++.h>
//qwerty47924692
using namespace std;
using ll = long long;
const ll N=2e5+29;
const string br="617283";
#define sz(a)(ll)a.size()
#define f first
#define s second
ll n,tin[N],tout[N],timer,pr[20][N],h[N];
vector<ll>g[N],ch;
void dfs(ll v){
    tin[v]=++timer;
    for(ll i=1;i<=19;i++){
        pr[i][v]=pr[i-1][pr[i-1][v]];
    }
    for(ll to:g[v]){
        if(to==pr[0][v])continue;
        pr[0][to]=v;
        h[to]=h[v]+1;
        dfs(to);
    }
    tout[v]=timer;
    if(tin[v]==tout[v]){
        ch.push_back(v);
    }
}
bool is_parent(ll x,ll y){
    return (tin[x]<=tin[y]&&tout[y]<=tout[x]);
}
ll get(ll x,ll y){
    for(ll i=19;i>=0;i--){
        if(!is_parent(pr[i][x],y))x=pr[i][x];
    }
    if(!is_parent(x,y))return pr[0][x];
    return x;
}
ll dist(ll v,ll u){
    ll x=get(v,u);
    return h[v]+h[u]-h[x]-h[x];
}
bool in(ll v,ll u,ll x){
    return (is_parent(v,x)&&is_parent(x,u))||(is_parent(u,x)&&is_parent(x,v))||(is_parent(x,v)&&is_parent(v,u))||(is_parent(x,u)&&is_parent(u,v));
}
ll calc(ll x,ll v,ll u){
    ll lca=get(v,u);
    ll ans=0;
    if(!is_parent(lca,x)){
        return dist(lca,x);
    }
    for(ll i=19;i>=0;i--){
        if(!in(lca,v,pr[i][x])&&!in(lca,u,pr[i][x]))ans+=dist(x,pr[i][x]),x=pr[i][x];
    }
    if(!in(lca,v,x)&&!in(lca,u,x)){
        ans+=dist(x,pr[0][x]);
        x=pr[0][x];
    }
    return ans;
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin>>n;
    for(ll i=1;i<n;i++){
        ll v,u;
        cin>>v>>u;
        g[v].push_back(u);
        g[u].push_back(v);
    }
    pr[0][1]=1;
    ch.push_back(1);
    dfs(1);
    ll mx=0,ans=0;
    for(auto i:ch){
        for(ll j:ch){
            if(i==j)continue;
            ll cur=0;
            for(ll k=1;k<=n;k++){
                cur=max(cur,calc(k,i,j));
            }
            cur*=dist(i,j);
            if(mx==cur){
                ans++;
            }
            if(mx<cur){
                mx=cur;
                ans=1;
            }
        }
    }
    cout<<mx<<' '<<ans/2;

}

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