Submission #667617

#	Time	Username	Problem	Language	Result	Execution time	Memory
667617		berr	Star Trek (CEOI20_startrek)	C++17	8 / 100	1096 ms	5156 KiB

startrek

#include <bits/stdc++.h>
using namespace std;
const int N=1e5+37;
vector<int> adj[N], adj2[N];
int huh, huuh;

int dfs2(int v, int p, int d)
{
    int f=1;

    if(d%2==0) f=0;

    int count=0, val=0;

    for(auto i: adj2[v])
    {
        if(i==p) continue;

        if(dfs2(i, v, d+1))
        {
         
            if(d%2==0){
                f=1;
            }
        }
        else
        {
            if(d%2) f=0;
        }
    }




    return f;
}


int dfs(int v, int p, int d)
{
    int f=1;

    if(d%2==0) f=0;

    int count=0, val=0;

    for(auto i: adj[v])
    {
        if(i==p) continue;

        if(dfs(i, v, d+1))
        {
         
            if(d%2==0){
                f=1;
            }
        }
        else
        {
            if(d%2) f=0;
        }
    }

    if(huh==v)
    {   
        if(dfs2(huuh, 0, d+1)) 
        {
            if(d%2==0) f=1;
        }
        else
        {
            if(d%2) f=0;
        }
    }

    return f;
}


signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int n, d; cin>>n>>d;


    for(int i=0; i<n-1; i++){
        int x, y; cin>>x>>y;

        adj[x].push_back(y);
        adj[y].push_back(x);

        adj2[x].push_back(y);
        adj2[y].push_back(x);
    }

    int ans=0;

    if(n<=1e4)
    {
        for(int i=1; i<=n; i++)
        {
            for(int l=1; l<=n; l++)
            {
                huh=i;
                huuh=l;
                if(dfs(1, 0, 0)) ans++;
            }
        }
    }

    cout<<ans;
}

Compilation message (stderr)

startrek.cpp: In function 'int dfs2(int, int, int)':
startrek.cpp:13:9: warning: unused variable 'count' [-Wunused-variable]
   13 |     int count=0, val=0;
      |         ^~~~~
startrek.cpp:13:18: warning: unused variable 'val' [-Wunused-variable]
   13 |     int count=0, val=0;
      |                  ^~~
startrek.cpp: In function 'int dfs(int, int, int)':
startrek.cpp:45:9: warning: unused variable 'count' [-Wunused-variable]
   45 |     int count=0, val=0;
      |         ^~~~~
startrek.cpp:45:18: warning: unused variable 'val' [-Wunused-variable]
   45 |     int count=0, val=0;
      |                  ^~~

• Subtask 1: 0 / 0
• Subtask 2: 0 / 7
• Subtask 3: 8 / 8
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20
• Subtask 8: 0 / 15