Submission #342993

#	Time	Username	Problem	Language	Result	Execution time	Memory
342993		leinad2	Village (BOI20_village)	C++17	50 / 100	167 ms	21612 KiB

Village

#include<bits/stdc++.h>
#define int long long
using namespace std;
int n, i, j, k, a, b, ans[100010], A[100010], res, cent, sz[100010], dep[100010], in[100010], revin[100010], cnt, res2, ans2[100010];
vector<int>adj[100010];
void dfs(int v, int par, int depth)
{
    in[v]=++cnt;
    dep[v]=depth;
    sz[v]=1;
    for(int i=0;i<adj[v].size();i++)
    {
        int p=adj[v][i];
        if(p==par)continue;
        dfs(p, v, depth+1);
        sz[v]+=sz[p];
    }
}
int centroid(int v, int par)
{
    for(int i=0;i<adj[v].size();i++)
    {
        int p=adj[v][i];
        if(p==par)continue;
        if(sz[p]*2>n)
        {
            return centroid(p, v);
        }
    }
    return v;
}
int f(int x)
{
    return ((x+(n/2))%n==0?n:(x+(n/2))%n);
}
void dfs2(int v, int par)
{
    vector<int>V;
    for(int i=0;i<adj[v].size();i++)
    {
        int p=adj[v][i];
        if(p==par)continue;
        dfs2(p, v);
        if(!A[p])V.push_back(p);
    }
    if(v==1&&V.size()==0)
    {
        ans2[ans2[adj[v][0]]]=1;
        ans2[1]=adj[v][0];
        res2+=2;
        return;
    }
    if(v==1&&V.size()==2)
    {
        res2+=4;
        ans2[v]=V[0];
        ans2[V[0]]=V[1];
        ans2[V[1]]=v;
        return;
    }
    if(V.size())
    {
        if(V.size()==2)
        {
            ans2[V[0]]=V[1];
            ans2[V[1]]=V[0];
            res2+=4;
        }
        else
        {
            A[v]=1;
            ans2[V[0]]=v;
            ans2[v]=V[0];
            res2+=2;
            if(V.size()>1)
            {
                for(i=1;i<V.size()-1;i++)
                {
                    ans2[V[i]]=V[i+1];
                    res2+=2;
                }
                ans2[V.back()]=V[1];
                res2+=2;
            }
        }
    }
}
main()
{
    for(scanf("%lld", &n);++i<n;)
    {
        scanf("%lld %lld", &a, &b);
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    dfs(1, 0, 0);
    cent=centroid(1, 0);
    cnt=0;
    dfs(cent, 0, 0);
    dfs2(1, 0);
    for(i=0;i++<n;)res+=dep[i]*2;
    for(i=0;i++<n;)
    {
        revin[in[i]]=i;
    }
    for(i=0;i++<n;)
    {
        ans[revin[i]]=revin[f(i)];
    }
    printf("%lld %lld\n", res2, res);
    for(i=0;i++<n;)printf("%lld ", ans2[i]);
    puts("");
    for(i=0;i++<n;)
    {
        printf("%lld ", ans[i]);
    }
}

Compilation message (stderr)

Village.cpp: In function 'void dfs(long long int, long long int, long long int)':
Village.cpp:11:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |     for(int i=0;i<adj[v].size();i++)
      |                 ~^~~~~~~~~~~~~~
Village.cpp: In function 'long long int centroid(long long int, long long int)':
Village.cpp:21:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |     for(int i=0;i<adj[v].size();i++)
      |                 ~^~~~~~~~~~~~~~
Village.cpp: In function 'void dfs2(long long int, long long int)':
Village.cpp:39:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |     for(int i=0;i<adj[v].size();i++)
      |                 ~^~~~~~~~~~~~~~
Village.cpp:77:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   77 |                 for(i=1;i<V.size()-1;i++)
      |                         ~^~~~~~~~~~~
Village.cpp: At global scope:
Village.cpp:88:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   88 | main()
      |      ^
Village.cpp: In function 'int main()':
Village.cpp:90:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   90 |     for(scanf("%lld", &n);++i<n;)
      |         ~~~~~^~~~~~~~~~~~
Village.cpp:92:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   92 |         scanf("%lld %lld", &a, &b);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 12
• Subtask 2: 19 / 38
• Subtask 3: 25 / 50