uva 10596 Morning Walk

#include<iostream>
#include<cmath>
#include<cstdio>
#include <cstring>
using namespace std;
int N, R, ok;
int head[10010], end[10010], vis[10010];
int degree[210], flag, num;
void dfs(int cur)
{
for(int i = 0; i < R; i++)
{
if(!vis[i] && head[i] == cur && end[i] == flag)
{
num++;
if(num == N)
ok = 1;
return;
}
if( !vis[i] && head[i] == cur)
{
num++;
vis[i] = 1;
dfs(end[i]);
}
}
}

int main()
{
while(cin >> N >> R)
{
memset(degree, 0, sizeof(degree));
for(int i = 0; i < R; i++)
{
cin >> head[i] >> end[i];
degree[ head[i] ]++;
degree[ end[i] ]++;
}
ok = 1;
if(R==0) ok = 0;
for(int i = 0; i < N; i++)
if( degree[i]%2 == 1)
{
ok = 0;
break;
}
memset(vis, 0, sizeof(vis));
if(ok)
{
flag = head[0];
dfs(head[0]);
}
if(ok) cout << "Possible" << endl;
else cout << "Not Possible" << endl;
}
return 0;
}

#include <iostream>
#include <cmath>
#include <cstdio>
#include <cstring>
using namespace std;
int N, R, ok;
int head, end, degree[210];
int main()
{
while(cin >> N >> R)
{
memset(degree, 0, sizeof(degree));
for(int i = 0; i < R; i++)
{
cin >> head >> end;
degree[ head ]++;
degree[ end ]++;
}
ok = 1;
if(R==0) ok = 0;
for(int i = 0; i < N; i++)
if( degree[i]%2 == 1)
{
ok = 0;
break;
}
if(ok) cout << "Possible" << endl;
else cout << "Not Possible" << endl;
}
return 0;
}