Index: lib/typical/unionfind.cpp
==================================================================
--- lib/typical/unionfind.cpp
+++ lib/typical/unionfind.cpp
@@ -17,10 +17,12 @@
 		{ return nc; }
 	int size(int a)
 		{ return sz[Find(a)]; }
 	int Find(int a)
 		{ return uf[a]==a ? a : uf[a]=Find(uf[a]); }
+		// Semi-compression w.o. recursion.
+		//{ while(uf[a] != a) a=uf[a]=uf[uf[a]]; return a; }
 	bool Union(int a, int b)
 		{
 			a = Find(a);
 			b = Find(b);
 			if( a != b )