4fd800b3a8 2011-02-23        kinaba: //-------------------------------------------------------------
4fd800b3a8 2011-02-23        kinaba: // Union-Find
4fd800b3a8 2011-02-23        kinaba: //   Balancing + Path-Compression : O(invAckermann)
4fd800b3a8 2011-02-23        kinaba: //
4fd800b3a8 2011-02-23        kinaba: // Verified by
4fd800b3a8 2011-02-23        kinaba: //   - SRM Member Pilot 2 Div1 LV2
4fd800b3a8 2011-02-23        kinaba: //-------------------------------------------------------------
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: struct UnionFind
4fd800b3a8 2011-02-23        kinaba: {
4fd800b3a8 2011-02-23        kinaba: 	vector<int> uf, sz;
4fd800b3a8 2011-02-23        kinaba: 	int nc;
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: 	UnionFind(int N): uf(N), sz(N,1), nc(N)
4fd800b3a8 2011-02-23        kinaba: 		{ for(int i=0; i<N; ++i) uf[i] = i; }
4fd800b3a8 2011-02-23        kinaba: 	int size()
4fd800b3a8 2011-02-23        kinaba: 		{ return nc; }
4fd800b3a8 2011-02-23        kinaba: 	int Find(int a)
4fd800b3a8 2011-02-23        kinaba: 		{ return uf[a]==a ? a : uf[a]=Find(uf[a]); }
4fd800b3a8 2011-02-23        kinaba: 	bool Union(int a, int b)
4fd800b3a8 2011-02-23        kinaba: 		{
4fd800b3a8 2011-02-23        kinaba: 			a = Find(a);
4fd800b3a8 2011-02-23        kinaba: 			b = Find(b);
4fd800b3a8 2011-02-23        kinaba: 			if( a != b )
4fd800b3a8 2011-02-23        kinaba: 			{
4fd800b3a8 2011-02-23        kinaba: 				if( sz[a] >= sz[b] ) swap(a, b);
4fd800b3a8 2011-02-23        kinaba: 				uf[a] = b;
4fd800b3a8 2011-02-23        kinaba: 				sz[b] += sz[a];
4fd800b3a8 2011-02-23        kinaba: 				--nc;
4fd800b3a8 2011-02-23        kinaba: 			}
4fd800b3a8 2011-02-23        kinaba: 			return (a!=b);
4fd800b3a8 2011-02-23        kinaba: 		}
4fd800b3a8 2011-02-23        kinaba: };