hoj1878
看是否所有定点的度都是偶数,并使用并查集看图是否连通。我开始因为没有判断是否连通而错了许多次。
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;
#define maxn 1005
int n, m, f[maxn], father[maxn];
int getanc(int a)
{
if (father[a] == a)
return a;
return father[a] = getanc(father[a]);
}
bool ok()
{
for (int i = 0; i < n; i++)
if (f[i] % 2 != 0 || getanc(i) != getanc(0))
return false;
return true;
}
int main()
{
//freopen("D:\\t.txt", "r", stdin);
while (scanf("%d", &n) != EOF && n != 0)
{
scanf("%d", &m);
for (int i = 0; i < n; i++)
father[i] = i;
memset(f, 0, sizeof(f));
for (int i = 0; i < m; i++)
{
int a, b;
scanf("%d%d", &a, &b);
a--;
b--;
father[getanc(a)] = getanc(b);
f[a]++;
f[b]++;
}
if (ok())
printf("1\n");
else
printf("0\n");
}
return 0;
}