Submission #580478

#	Time	Username	Problem	Language	Result	Execution time	Memory
580478		yutabi	Shymbulak (IZhO14_shymbulak)	C++14	50 / 100	1592 ms	8232 KiB

shymbulak

#include <bits/stdc++.h>
using namespace std;


#define pb push_back


typedef long long ll;
typedef pair <ll,ll> ii;


int ans;
int best=-1;

int n;

vector <vector <int> > graph;

queue <int> q;
vector <int> d;
vector <int> c;
vector <bool> v;


int main()
{
    scanf("%d",&n);

    graph=vector <vector <int> > (n);

    for(int i=0;i<n;i++)
    {
        int a,b;

        scanf(" %d %d",&a,&b);
        a--,b--;

        graph[a].pb(b);
        graph[b].pb(a);
    }

    for(int i=0;i<n;i++)
    {
        d=vector <int> (n,-1);
        c=vector <int> (n,0);
        v=vector <bool> (n,0);

        d[i]=0;
        c[i]=1;

        q.push(i);

        while(q.size())
        {
            int a=q.front();
            q.pop();

            if(v[a]==1)
            {
                continue;
            }

            v[a]=1;

            if(d[a]>best)
            {
                best=d[a];
                ans=0;
            }

            if(d[a]==best)
            {
                ans+=c[a];
            }

            for(int j=0;j<graph[a].size();j++)
            {
                if(v[graph[a][j]]==0)
                {
                    q.push(graph[a][j]);

                    if(d[graph[a][j]]>d[a]+1 || d[graph[a][j]]==-1)
                    {
                        d[graph[a][j]]=d[a]+1;
                        c[graph[a][j]]=0;;
                    }

                    if(d[graph[a][j]]==d[a]+1)
                    {
                        c[graph[a][j]]+=c[a];
                    }
                }
            }
        }
    }

    ans/=2;

    printf("%d",ans);
}

Compilation message (stderr)

shymbulak.cpp: In function 'int main()':
shymbulak.cpp:76:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |             for(int j=0;j<graph[a].size();j++)
      |                         ~^~~~~~~~~~~~~~~~
shymbulak.cpp:27:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
shymbulak.cpp:35:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |         scanf(" %d %d",&a,&b);
      |         ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 20 / 20
• Subtask 3: 0 / 50