day21: saturation logic, but removing points to early

day21/notes.org

@@ -39,3 +39,52 @@ my input is 131 chars of width.
 so neighboring are necessarily of different phase.
 could compute phase of (0,0)
 and adjust from that
+** TODO remake 'ReachableBySteps' into 'CountReachableBySteps' returning int
+** TODO make it take 'isInitialCountOdd' - to know phase of {0,0} field
+current phase can be determined by initial phase and current N
+
+if initial count is odd, and now it's odd number, we made even iterations, so (0,0) is in even state
+if initial count is even, and now it's even number, we made even iterations, so (0,0) is in even state
+
+** DONE make neighbors take set of saturated fields
+and not produce points on those fields
+** DONE for field calculate what would be amount of points in each phase
+...........
+.....###.#.
+.###.##..#.
+..#.#...#..
+....#.#....
+.##..S####.
+.##..#...#.
+.......##..
+.##.#.####.
+.##..##.##.
+...........
+*** getting 39 and 42
+let's check
+42 is even?
+*** hmmm
+EOEOEOEOEOE
+OEOEO###O#O
+E###E##OE#E
+OE#E#EOE#EO
+EOEO#O#OEOE
+O##EOE####O
+E##OE#EOE#E
+OEOEOEO##EO
+E##O#O####E
+O##EO##E##O
+EOEOEOEOEOE
+*** yes, sounds good
+
+
+** TODO after getting all new points. get coords of all fields we're working on.
+( there already should be no points in saturated fields )
+for each such field, check if it is saturated.
+
+- can be done by comparing the phase with amount of points on saturated
+
+if field saturated - add the coord into set
+and remove all the points
+** TODO on the last step, when n is 0
+return len(startingAt) + (all saturated fields) * (amount of elems in their phase)