Documentation - more README

Author: rahul1947

BinaryHeap.java

@@ -11,6 +11,15 @@
 
 import java.util.NoSuchElementException;
 
+/**
+ * Implementing Priority Queue (as Binary Heaps) using Arrays.
+ * NOTE: add(x) and remove() returns true for successful 
+ * operations, else throws an Exception.
+ * 
+ * IndexedHeap is extension of Binary Heap with decreaseKey() 
+ * implementation thereby extending Index interface to update
+ * indices appropriately. 
+ */
 public class BinaryHeap<T extends Comparable<? super T>> {
 	Comparable[] pq; // Priority Queue
 	int capacity; // maximum size of Priority Queue

README.txt

@@ -26,6 +26,37 @@ MST.java:
 
 NOTE: the current directory must contain rbk directory with rbk/Graph.java
 
+----------------------------------------------------------------------------
+# OBSERVATIONS
+1. In BinaryHeap - add(x), and remove() throws exception when they 
+   encounter full and empty queue conditions respectively. But, offer(x), 
+   and poll() silently returns false for the above conditions. 
+   
+2. In BinaryHeap - we could have used resize() as we try to add an element to
+   fully occupied queue. But, as we are dealing with fixed graph, the 
+   resize() is never being called.
+   
+3. In MST Algorithms - the early exit optimization is applied but, when 
+   tested it appears that Prim3 doesn't need such optimization. 
+   Note that this optimization only helps in saving computations after you add 
+   the last (n-1)th edge to the MST. 
+
+4. For Prim's Algorithm - Take 2:
+   We may not need to use the constructor MSTVertex(MSTVertex u).
+   As we could store the original vertex information for each MSTVertex,
+   we can make copies of new MSTVertices out of the original Vertex, 
+   instead of it's MSTVertex copy.
+   For e.g. if we have Vertex v, we can use -
+   MSTVertex vCopy = new MSTVertex(v) instead of
+   MSTVertex vCopy = new MSTVertex(get(v)).
+
+   These copies are used to store different distance and parent values 
+   whereas, get(v) has the information about 'seen'ness of all MSTVertices 
+   made out of v. 
+   
+ 5. For Prim2 and Prim3, we are storing the information about the edge 
+   which reaches out to this MSTVertex. It is used to form mst<Edge>.
+     
 ----------------------------------------------------------------------------
 # RESULTS
 +------------------------------------------------------------------------+
@@ -82,4 +113,9 @@ NOTE:
   Existing Processor: Intel® Core™ i5-8250U CPU @ 1.60GHz × 8
   Memory: 7.5 GiB
 
-- All necessary results are stored in the result directory for reference.
+- All necessary results are stored in the result directory for reference.
+
+- These files are not good examples for determining efficiency of Prim3 
+  over Prim1. For sparse graphs like these, Prim1 could beat Prim3, but 
+  when graph grows dense Prim3 could easily beat Prim1.
+