南阳理工OJ_题目42 一笔画问题

#include <iostream>
#include <cstring>

using namespace std;

void dfs(int n);

int a[1010];
bool vis[1010];
bool m[1010][1010];
int P;
int Q;

int main()
{
    int T;
    cin >> T;
    while(T--)
    {
        int A, B;
        cin >> P >> Q;
        memset(a, 0, sizeof(a));
        memset(vis, 0, sizeof(vis));
        memset(m, 0, sizeof(m));
        for(int i = 1; i <= Q; i++)
        {
            cin >> A >> B;
            m[A][B] = 1;
            m[B][A] = 1;
            a[A]++;
            a[B]++;
        }
        dfs(1);
        int flag = 1;
        int num = 0;
        for(int i = 1; i <= P; i++)
        {
            if(vis[i] == 0)
            {
                flag = 0;
                break;
            }
            if(a[i] % 2 == 1)
                num++;
        }
        if(flag == 1 && num <= 2)
            cout << "Yes\n";
        else
            cout << "No\n";

    }
}

void dfs(int n)
{
    vis
 = 1;
    for(int i = 1; i <= P; i++)
        if(m
[i] == 1 && vis[i] == 0)
            dfs(i);
}