Light OJ 1009

#include<bits/stdc++.h>
using namespace std;
const int maxn = 20000 + 131;
struct Node {
    int One, Zre;
}N[maxn / 2];
vector<int> E[maxn];
bool Vis[maxn];
int Cnt ;

void DFS(int e, int k)
{
    for(int i = 0; i < E[e].size(); ++i)
    {
        if(Vis[E[e][i]] == false)
        {
            //cout << "This is E : " << E[e][i] << endl;
            Vis[E[e][i]] = true;
            if(k == 0) N[Cnt].Zre ++;
            else N[Cnt].One ++;
            DFS(E[e][i], !k);
        }
    }
}

int Solve()
{
    Cnt = 0;
    for(int i = 0; i < maxn; ++i)
    {
        if(Vis[i] == false && E[i].size())
        {
            Cnt ++;
            N[Cnt].One = 1;
            Vis[i] = true;
            DFS(i, 0);
        }
    }
    /*for(int i = 1; i <= Cnt; ++i)
    {
        cout << N[i].Zre << "  " << N[i].One << endl;
    }*/
    int Ans = 0;
    for(int i = 1; i <= Cnt; ++i)
        Ans += max(N[i].Zre, N[i].One);
    return Ans;
}

void INIT()
{
    memset(N,0,sizeof(N));
    memset(Vis,0,sizeof(Vis));
    for(int i = 0; i < maxn; ++i)
        E[i].clear();
}

int main()
{
    int t, n, u ,v;
    scanf("%d", &t);
    for(int kase = 1; kase <= t; ++ kase)
    {
        INIT();
        scanf("%d", &n);
        for(int i = 0; i < n; ++i)
        {
            scanf("%d %d", &u, &v);
            E[u].push_back(v);
            E[v].push_back(u);
        }
        int ret = Solve();
        printf("Case %d: %d\n", kase, ret);
    }
}