hdu 1878 欧拉回路

#include<stdio.h>
#define N 1005
int mark
,rank
,num
;
int n,m;
void value()
{
int i;
for(i=0;i<=n;i++)
{
mark[i]=i;
rank[i]=1;
num[i]=0;
}
return ;
}
int find(int x)
{
while(x!=mark[x])
x=mark[x];
return x;
}
void Union(int x,int y)
{
x=find(x);
y=find(y);
if(x==y)
return ;
if(rank[x]>rank[y])
{
mark[y]=x;
rank[x]+=rank[y];
}
else
{
mark[x]=y;
rank[y]+=rank[x];
}
return ;
}
int main()
{
int i;
int x,y;
int count1,count2;
while(scanf("%d",&n),n)
{
scanf("%d",&m);
value();
while(m--)
{
scanf("%d%d",&x,&y);
num[x]++;
num[y]++;
Union(x,y);
}
count1=count2=0;
for(i=1;i<=n;i++)
{
if(mark[i]==i)
count1++;
if(num[i]%2==0)
count2++;
}
if(count1==1&&count2==n)
printf("1\n");
else
printf("0\n");
}
return 0;
}