From http://acm.nyist.net/JudgeOnline/bestcode.php?pid=207

NYOJ/207_iphxer.cpp

@@ -0,0 +1,61 @@
+ 
+#include<iostream>
+#include<hash_map>
+//#include"iphxer_h.h"
+#include<string>
+#include<cstring>
+#include<cstdio>
+#include<map>
+
+using namespace std;
+#define maxsize 50100
+int rank1[maxsize];//相对于根元素的权值0：同类，1：x吃father[x],2表示被father[x] 吃
+int father[maxsize];
+void initU(int n){
+	for(int i=0;i<n;i++){
+		father[i]=i;
+		rank1[i]=0;
+	}
+}
+int Find(int x){
+	if(father[x]==x)return x;
+	int t=father[x];//保存更新前的father位置，用来更新子rank
+	father[x]=Find(father[x]);
+	rank1[x]=(rank1[t]+rank1[x])%3;//计算相对于根节点的rank值
+	return father[x];
+}
+//把y合并到x中，关系为d
+void Union(int x,int y,int d)
+{
+	int xf=Find(x);
+	int yf=Find(y);
+	father[xf]=yf;//合并到y上
+	rank1[xf]=(rank1[y]-rank1[x]+3+d)%3;	
+}
+
+int main()
+{
+	 
+	int i,n,m;
+	int d,x,y,xf,yf;
+	int sum=0;
+	scanf("%d%d",&n,&m);
+	initU(n);
+	for(int i=0;i<m;i++){
+		scanf("%d%d%d",&d,&x,&y);
+		if(x>n||y>n||(d==2&&x==y))
+			++sum;
+		else{
+			xf=Find(x);
+			yf=Find(y);
+			if(xf==yf){
+				if((rank1[x]-rank1[y]+3)%3!=d-1)
+					sum++;
+			}else{
+				Union(x,y,d-1);
+			}
+		}
+	}
+	cout<<sum<<endl;
+}
+