HDU-3018 Ant Trip（欧拉回路）

#include <bits/stdc++.h>
#define _for(i,a,b) for(int i = (a);i < (b);i ++)
using namespace std;

const int MAXV = 100003;
int V,E,Vis[MAXV];
vector<int> G[MAXV];

int dfs(int u)
{
    if(Vis[u]) return 0;
    Vis[u] = 1;
    int sz = G[u].size(),r = sz&0x1;
    _for(i,0,sz) r += dfs(G[u][i]);
    return r;
}

int main()
{
    for(int a,b,n;cin >> V >> E;n = 0)
    {
        _for(i,0,V+1) G[i].clear();
        memset(Vis,0,sizeof(Vis));
        _for(i,0,E)
        {
            cin >> a >> b;
            if(a==b) continue;
            G[a-1].push_back(b-1),G[b-1].push_back(a-1);
        }

        _for(i,0,V)
        {
            if(Vis[i] || G[i].empty())    continue;
            n ++,n += max(0,dfs(i)/2-1);
        }
        cout << n << endl;
    }
    return 0;
}