Update README.md to include topological order

README.md

@@ -688,15 +688,27 @@ The following messages may be sent by an engine to a controller:
 
 # Footrace Generator Design
 
-The footrace generator necessitated the use of a dynamic programming algorithm rather than a greedy algorithm. If a greedy were used, it would 
-value the most movement north but would place the piece in situations that require more moves to reach the end. 
-`findStartingSituationAndFastestMoveSequence(position)` is the main dynamic programming algorithm.
+The design for the footrace generator is as follows:
 
-The code uses `ONE_LANE_GAME` and `TWO_LANE_GAME` to generate the puzzles. The algorithm is only used for the `ONE_LANE_GAME` to generate a path. 
+*   The footrace generator necessitated the use of a dynamic programming algorithm
+    rather than a greedy algorithm. If a greedy were used, it would value the most
+    movement north but would place the piece in situations that require more moves
+    to reach the end.
+
+*   `findStartingSituationAndFastestMoveSequence(position)` is the main dynamic
+    programming algorithm.
+
+*   The code uses `ONE_LANE_GAME` and `TWO_LANE_GAME` to generate the puzzles.
+    The algorithm is only used for the `ONE_LANE_GAME` to generate a path. 
     The `ONE_LANE_GAME` is then mirrored to make the `TWO_LANE_GAME`.
 
-When the dynamic programming algorithm is run, the board contains pawns and towers.
+*   When the dynamic programming algorithm is run, the board contains pawns and towers.
+
+*   Each vertex of the DAG is a `Situation`. These vertices are added to the DAG using
+    `selectBetterBackpointer()`.
 
-Each vertex of the DAG is a `Situation`. These vertices are added to the DAG using `selectBetterBackpointer()`.
+*   Each edge of the DAG is a move. The algorithm finds the move leading to a `Situation`
+    in the `predecessor` index of `backpointersTable`.
 
-Each edge of the DAG is a move. The algorithm finds the move leading to a `Situation` in the `predecessor` index of `backpointersTable`.
+*   The topological order is determined by comparing the y values of two `Situation` objects.
\ No newline at end of file
+    If there is a tie, the x values are compared.
\ No newline at end of file