POJ 1182

#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <set>

using namespace std;
#define maxn 50100

int fa[maxn], def[maxn];

int find( int x )
{
    if(fa[x] == x)
       return x;

     int tem = find(fa[x]);
     def[x] = (def[x] + def[fa[x]] )%3;
    // cout<<x<<"fa-> def "<<fa[x]<<"-> "<<def[x]<<endl;
     return fa[x] = tem;
}

int unio( int x, int y, int val)
{
    int fx = find(x);
    int fy = find(y);

    if(fx != fy)
    {
        fa[fx] = fy;
        def[fx] = ( 3 - def[x] + val + def[y])%3;
    }
}
int main()
{
     int n, k;
     scanf("%d %d",&n, &k);
     
         int kind, a, b;
         int ans = 0;
         for( int i = 0 ; i <= n; i++)
         {
             fa[i] = i;
             def[i] = 0;
         }
         for( int i = 0 ; i < k; i++)
         {
             scanf("%d %d %d",&kind, &a, &b);
             if(a > n || b > n)
                  ans ++;
             else if(a == b && kind == 2)
                   ans ++;
             else
             {   int fa = find(a);
                 int fb = find(b);

                 if(fa != fb)
                 {
                      unio(a, b, kind-1);
                 }
                 else
                 {
                    if(def[a] != ( def[b] +  kind - 1) %3)
                     ans++;
                 }

             }
         }
        printf("%d\n",ans);
     
}