C :

#include<stdio.h>
int main()
{
  int n,m,a[1000]={0},i,temp,b,c,count;
  while(scanf("%d %d",&n,&m)!=EOF&&n!=0)
    {
      temp=m;count=0;
      while(m--)
      {
        scanf("%d %d",&b,&c);
        a[b]++;a[c]++;
      }
      for(i=1;i<=temp*2;i++)
       {
        if(a[i]%2!=0){count=1;break;}
       }
       if(count==0)printf("1\n");
       else printf("0\n");
       for(i=0;i<n;i++)
       a[i]=0;
    }
  return 0;
}

C++ :

#include <cstdio>
#include <vector>
#include <cstring>

const int N = 1005;

std::vector < int > v[N];
bool vis[N];

void dfs(int x) {
    vis[x] = true;
    for (std::vector < int >::iterator it = v[x].begin(); it != v[x].end(); ++it)
        if (!vis[*it])
            dfs(*it);
}

int main() {
    int n, m;
    while (scanf("%d", &n) && n > 0) {
        scanf("%d", &m);
        for (int i = 0; i < N; ++i)
            v[i].clear();
        while (m--) {
            int x, y;
            scanf("%d %d", &x, &y);
            v[x].push_back(y);
            v[y].push_back(x);
        }
        memset(vis, 0, sizeof(vis));
        dfs(1);
        int ans = 1;
        for (int i = 1; i <= n; ++i) {
            if (v[i].size() % 2 == 1)
                ans = 0;
            if (!vis[i])
                ans = 0;
        }
        printf("%d\n", ans);
    }
    return 0;
}

Pascal :

var
 du:array[1..1010] of longint;
 n,m,x,y,i:longint;
 fg:boolean;

begin
 while true do
  begin
   read(n);
   if n=0 then break;
   readln(m);
   fillchar(du,sizeof(du),0);
   for i:=1 to m do
    begin
     readln(x,y);
     inc(du[x]);
     inc(du[y]);
    end;
   fg:=true;
   for i:=1 to m do
    if odd(du[i]) then
     begin
      fg:=false;
      break;
     end;
   if fg then writeln('1') else writeln('0');
  end;
end.