From b10a6250b1c6f336df6c8ca77b729c48d81cf8e2 Mon Sep 17 00:00:00 2001
From: efim <efim.nefedov@nordigy.ru>
Date: Thu, 21 Dec 2023 12:36:07 +0000
Subject: [PATCH] day21: wrong answer AND slow. need to scrap

---
 day21/stepCounter.go | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/day21/stepCounter.go b/day21/stepCounter.go
index 8d9764a..2cc4366 100644
--- a/day21/stepCounter.go
+++ b/day21/stepCounter.go
@@ -9,7 +9,7 @@ import (
 
 func Run() (result int) {
 	fmt.Print("hello day21")
-	filename := "day21/example"
+	filename := "day21/input"
 	field := ReadField(filename)
 	log.Print(field)
 
@@ -25,14 +25,14 @@ func Run() (result int) {
 	// 	field.PrintCoord(reachableBySteps, 1)
 	// }
 
-	steps := 50
+	steps := 26501365
 	reachableBySteps := field.ReachableBySteps(
 		steps,
 		map[FieldPoint]any{
 			FieldPoint{
 				InField: Coord{Row: field.RowStart, Col: field.ColStart},
 			}: struct{}{}},
-		make(map[Coord]any),
+		make(map[Coord]int),
 		steps)
 	result = reachableBySteps
 	log.Print("reachable after steps : ", steps, result)
@@ -60,7 +60,7 @@ type FieldPoint struct {
 	MetaField Coord
 }
 
-func (f Field) ReachableBySteps(n int, startingAt map[FieldPoint]any, saturatedFields map[Coord]any, initialSteps int) (countReachable int) {
+func (f Field) ReachableBySteps(n int, startingAt map[FieldPoint]any, saturatedFields map[Coord]int, initialSteps int) (countReachable int) {
 	if n%100 == 0 {
 		log.Println("going step: ", n)
 	}
@@ -78,7 +78,7 @@ func (f Field) ReachableBySteps(n int, startingAt map[FieldPoint]any, saturatedF
 			}
 		}
 
-		return sizeOfUnsaturated
+		return sizeOfUnsaturated + sizeOfSaturated
 	}
 	// else collect directly available
 
@@ -97,21 +97,22 @@ func (f Field) ReachableBySteps(n int, startingAt map[FieldPoint]any, saturatedF
 	for workedUponFieldCoord, amount := range metaFields {
 		isEven := FieldIsInEven(initialSteps, n, workedUponFieldCoord)
 		if workedUponFieldCoord.Col == 0 && workedUponFieldCoord.Row == 0 {
-			log.Printf("checking %+v : %d as worked fields for saturation. isEven %t", workedUponFieldCoord, amount, isEven)
+			// log.Printf("checking %+v : %d as worked fields for saturation. isEven %t", workedUponFieldCoord, amount, isEven)
 		}
 		if isEven && amount == f.SaturatedEvenCount {
 			log.Printf(">>> adding %+v to saturated, with amount %d\n", workedUponFieldCoord, amount)
-			saturatedFields[workedUponFieldCoord] = struct{}{}
+			saturatedFields[workedUponFieldCoord] = n
 		}
 		if !isEven && amount == f.SaturatedOddCount {
 			log.Printf(">>> adding %+v to saturated, with amount %d\n", workedUponFieldCoord, amount)
-			saturatedFields[workedUponFieldCoord] = struct{}{}
+			saturatedFields[workedUponFieldCoord] = n
 		}
 	}
 
 	for point := range oneStepExpanded {
-		_, fromSaturated := saturatedFields[point.MetaField]
-		if fromSaturated {
+		saturatedAtStep, fromSaturated := saturatedFields[point.MetaField]
+		// hack. to not remove points from saturated fields too early
+		if fromSaturated && (saturatedAtStep - n > 200) {
 			delete(oneStepExpanded, point)
 		}
 	}
@@ -139,7 +140,7 @@ func FieldIsInEven(initialSteps, currentSteps int, metaCoord Coord) bool {
 	}
 }
 
-func (f Field) Neighbors(c FieldPoint, saturatedFields map[Coord]any) (resut []FieldPoint) {
+func (f Field) Neighbors(c FieldPoint, saturatedFields map[Coord]int) (resut []FieldPoint) {
 	closeCoords := []FieldPoint{
 		{InField: Coord{Row: c.InField.Row + 1, Col: c.InField.Col}, MetaField: c.MetaField},
 		{InField: Coord{Row: c.InField.Row - 1, Col: c.InField.Col}, MetaField: c.MetaField},