Quick find class - study union find algorithm following the blog: http://blog.csdn.net/dm_vincent/article/details/7655764

quickFind_Algorithm.cs

/// <summary>
    /// Study notes for the blog about union find
    /// http://blog.csdn.net/dm_vincent/article/details/7655764
    /// Quick-find algorithm
    /// </summary>
    public class QuickFind
    {  
        private int[] id;    // access to component id (site indexed)  
        private int   count; // number of components 
 
        public QuickFind(int N)  
        {  
            // Initialize component id array.  
            count = N;  
            id = new int[N];
            for (int i = 0; i < N; i++)
            {
                id[i] = i;
            }
        }  

        public int GetCount()  
        { 
            return count; 
        }  

        public bool Connected(int p, int q)  
        { 
            return Find(p) == Find(q); 
        }  

        public int Find(int p)  
        { 
            return id[p]; 
        }  

        public void Union(int p, int q)  
        {            
            int pID = Find(p);  
            int qID = Find(q);


            if (pID == qID)
            {
                return;
            }
        
            // Find the pID, and make them one group
            for (int i = 0; i < id.Length; i++)
            {
                if (id[i] == pID)
                {
                    id[i] = qID;
                }
            }

            // update count of groups
            count--;  
        }  
    }