제출 #653069

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
653069		MilosMilutinovic	Hard route (IZhO17_road)	C++14	0 / 100	8 ms	11988 KiB

road

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
const int N=500050;
const int L=25;
int n,par[N][L],dep[N];
vector<int> E[N],l;
void DFS(int v,int pv){
    par[v][0]=pv;
    dep[v]=dep[pv]+1;
    if(E[v].size()==1)l.pb(v);
    for(int u:E[v])if(u!=pv)DFS(u,v);
}
int Lift(int v,int k){for(int i=L-1;~i;i>=0)if(k>>i&1)v=par[v][i];return v;}
int LCA(int v,int u){
    if(dep[v]>dep[u])swap(u,v);
    for(int i=L-1;~i;i--)if(dep[par[u][i]]>=dep[v])u=par[u][i];
    for(int i=L-1;~i;i--)if(par[u][i]!=par[v][i])u=par[u][i],v=par[v][i];
    return v==u?v:par[v][0];
}
int Dist(int u,int v){return dep[u]+dep[v]-2*dep[LCA(u,v)];}
bool was[N];
int Solve(int u,int v){
    for(int i=1;i<=n;i++)was[i]=false;
    int l=LCA(u,v);
    deque<pair<int,int> > q;
    q.pb({l,0});
    was[l]=true;
    for(int i=u;i!=l;i=par[i][0])q.pb({i,0}),was[i]=true;
    for(int i=v;i!=l;i=par[i][0])q.pb({i,0}),was[i]=true;
    int d=0;
    while(!q.empty()){
        pair<int,int> p=q.front();
        q.pop_front();
        int x=p.first;
        d=max(d,p.second);
        for(auto&y:E[x])if(!was[y])q.pb({y,p.second+1}),was[y]=true;
    }
    return d;
}
int main(){
    scanf("%i",&n);
    for(int i=1;i<n;i++){
        int u,v;
        scanf("%i%i",&u,&v);
        E[u].pb(v);
        E[v].pb(u);
    }
    if(n==2){
        printf("0 1");
        return 0;
    }
    int root=1;
    for(int i=1;i<=n;i++)if(E[i].size()>1)root=i;
    DFS(root,root);
    for(int j=1;j<L;j++)for(int i=1;i<=n;i++)par[i][j]=par[par[i][j-1]][j-1];
    int sz=(int)l.size();
    if(sz==2){
        printf("0 1");
        return 0;
    }
    pair<long long,int> ans={-1,0};
    for(int i=0;i<sz;i++)for(int j=(i+1)%sz;j<=(i+1)%sz;j++){
        long long d=Solve(l[i],l[j])*1LL*Dist(l[i],l[j]);
        if(ans.first<d)ans={d,1};
        else if(ans.first==d)ans.second++;
    }
    printf("%lld %i",ans.first,ans.second);
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

road.cpp: In function 'int Lift(int, int)':
road.cpp:14:41: warning: for increment expression has no effect [-Wunused-value]
   14 | int Lift(int v,int k){for(int i=L-1;~i;i>=0)if(k>>i&1)v=par[v][i];return v;}
      |                                        ~^~~
road.cpp: In function 'int main()':
road.cpp:42:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |     scanf("%i",&n);
      |     ~~~~~^~~~~~~~~
road.cpp:45:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         scanf("%i%i",&u,&v);
      |         ~~~~~^~~~~~~~~~~~~~

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