Updated readme to explain algorithm

README.md

@@ -15,4 +15,14 @@ npm start 1x2,2x3,5x6,7x8,11x12,10x1,9x8,3x4,5x4,8x4,9x7,5x7 10
 ### Details
 - Dominoes are represented with the numbered sides separated by an 'x'. e.g.: 1x2 or 10x11
 - The first argument to the program must be a comma separated list of dominoes
-- The second argument must be the number for the side you're trying to connect to
+- The second argument must be the number for the side you're trying to connect to
+
+### How's it work?
+This program uses a lazy algorithm to traverse all possible chains given a sequence of dominoes starting from the specified side.
+
+The algorithm has three phases:
+1. Find all possible "graphs" for the chain of dominoes. A "graph" in this case is a directed graph from each domino to every other possible domino it could be paired to.
+2. Traverse all possible paths for each generated graph starting from the specified side.
+3. Return the longest path found from all the paths we've generated.
+
+The graph is represented as a map of side values to all the dominoes that contain that side.