NYIST OJ 题目42 一笔画问题

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

const int maxn = 1000 + 10;
int tott[maxn];
int father[maxn];

int find(int x)
{
if (x != father[x]) father[x] = find(father[x]);
return father[x];
}

int main()
{
int T;
scanf("%d", &T);
while (T--)
{
int i, n, m, u, v;
scanf("%d%d", &n, &m);
for (i = 0; i <= n; i++) father[i] = i;
memset(tott, 0, sizeof(tott));
for (i = 0; i < m; i++)
{
scanf("%d%d", &u, &v);
int fu = find(u);
int fv = find(v);
if (fu != fv) father[fu] = fv;
tott[u]++;
tott[v]++;
}
int ji = 0, ou = 0;
for (i = 1; i <= n; i++)
{
if (tott[i] == 0) continue;
if (tott[i] % 2 == 0) ou++;
else ji++;
}
int jieguo = 0;
int th = find(1);
for (i = 2; i <= n; i++)
{
int tg = find(i);
if (tg != th) break;
}
if (i == n + 1) jieguo = 1;
if (jieguo == 1)
{
if (ji == 0 || ji == 2) jieguo = 1;
else jieguo = 0;
}
if (jieguo == 1) printf("Yes\n");
else printf("No\n");
}
return 0;
}