食物链 poj 1182

#include<iostream>
#include<stdio.h>
#define max1 50005
using namespace std;
int par[max1],ran[max1];
int n,k;
int find(int a)
{
    if(a!=par[a])
    {
        int t=par[a];
        par[a]=find(par[a]);
        ran[a]=(ran[a]+ran[t])%3;

    }
    return par[a];
}
void build(int d,int x,int y)
{
    int fx=find(x);
    int fy=find(y);
    par[fx]=fy;
    ran[fx]=(3-ran[x]+d+ran[y])%3;
}

int main()
{

    while((scanf("%d%d",&n,&k))!=EOF){
        for(int i=1; i<=n; i++)
        {
            par[i]=i;
            ran[i]=0;
        }
        ran[0]=0;
        int d,x,y;
        int ans=0;
        for(int i=0; i<k; i++)
        {
            scanf("%d%d%d",&d,&x,&y);
            if(x>n||y>n||(x==y&&d==2))
            {
                ans++;
            }
            else
            {
                int fx=find(x);
                int fy=find(y);
                if(fx==fy)
                {
                    //cout<<x<<"dd"<<y<<"ran:"<<ran[x]<<"   "<<ran[y]<<endl;
                    if((ran[x]-ran[y]+3)%3!=d-1)
                        ans++;
                }

                else
                {
                    build(d-1,x,y);
                    // cout<<d<<"  "<<x<<"   "<<y<<endl;
                }
            }

        }
        printf("%d\n",ans);}
        return 0;
}