delete pics to save space

2.1160.cpp

@@ -0,0 +1,28 @@
+#include<cstdio>
+const int maxn=100010;
+int x,y,fa[maxn];
+int ff(int x)
+{
+	return fa[x]!=x?fa[x]=ff(fa[x]):x;
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	while(scanf("%d",&x)==1)
+	{
+		for(int i=0;i<maxn;i++) fa[i]=i;
+		int res=0;
+		while(x!=-1)
+		{
+			scanf("%d",&y);
+			x=ff(x);y=ff(y);
+			if(x==y) ++res;
+			else fa[x]=y;
+			scanf("%d",&x);
+		}
+		printf("%d\n",res);
+	}
+	return 0;
+}