From 6868307aed6d5c47edb0ce7ab14dbf5b9a4e2787 Mon Sep 17 00:00:00 2001
From: Stefan Harmuth <stefan.harmuth@docomodigital.com>
Date: Thu, 21 Oct 2021 02:59:44 +0200
Subject: [PATCH] day13,p1: utilize new A-Star pathfinder in GridToggle

---
 day13/day.go | 62 ++++++++++++++--------------------------------------
 1 file changed, 16 insertions(+), 46 deletions(-)

diff --git a/day13/day.go b/day13/day.go
index 8256a9a..f65a6b6 100644
--- a/day13/day.go
+++ b/day13/day.go
@@ -7,6 +7,11 @@ import (
 	"tools"
 )
 
+type mazeNode struct {
+	x, y, nodeType int // ß = wall, 1 = path, 2 = start, 3 = target
+	neighbours     []mazeNode
+}
+
 const mazeHangover int = 10
 
 var favNumber, targetX, targetY int
@@ -44,69 +49,34 @@ func buildMaze(maxX, maxY int) tools.GridToggle {
 	return maze
 }
 
-func printMaze(maze, path tools.GridToggle) {
+func printMaze(maze tools.GridToggle, path []tools.Coordinate) {
+	pathMap := make(map[tools.Coordinate]int)
+	for i, c := range path {
+		pathMap[c] = i
+	}
 	for y := 0; y <= maze.MaxY; y++ {
 		for x := 0; x <= maze.MaxX; x++ {
 			if (x == targetX && y == targetY) || (x == 1 && y == 1) {
 				fmt.Print("X")
-			} else if path.State(x, y) {
+			} else if _, ok := pathMap[tools.Coordinate{X: x, Y: y}]; ok {
 				fmt.Print("O")
-			} else if maze.State(x, y) {
-				fmt.Print("#")
-			} else {
+			} else if !maze.State(x, y) {
 				fmt.Print(".")
+			} else {
+				fmt.Print("#")
 			}
 		}
 		fmt.Println()
 	}
 }
 
-func shortestPathToTarget(maze, visited tools.GridToggle, startX, startY int) tools.GridToggle {
-	minSteps := fullGrid.GetOnCount()
-	var newVisited tools.GridToggle
-	visited.Set(startX, startY, tools.On)
-	origVisited := visited.Copy()
-
-	if startX == targetX && startY == targetY {
-		return visited
-	}
-
-	toCheckList := []tools.Coordinate{
-		{startX - 1, startY},
-		{startX + 1, startY},
-		{startX, startY - 1},
-		{startX, startY + 1},
-	}
-
-	for _, toCheck := range toCheckList {
-		if toCheck.X < 0 || toCheck.Y < 0 || toCheck.X > maze.MaxX || toCheck.Y > maze.MaxY {
-			continue
-		}
-
-		if !maze.State(toCheck.X, toCheck.Y) && !visited.State(toCheck.X, toCheck.Y) {
-			newVisited = shortestPathToTarget(maze, origVisited.Copy(), toCheck.X, toCheck.Y)
-			if newVisited.State(targetX, targetY) && newVisited.GetOnCount() < minSteps {
-				minSteps = newVisited.GetOnCount()
-				visited = newVisited
-			}
-		}
-	}
-
-	if minSteps < fullGrid.GetOnCount() {
-		return visited
-	} else {
-		return fullGrid
-	}
-}
-
 func Part1(puzzle tools.AoCPuzzle) interface{} {
 	favNumber, targetX, targetY = parseInput(puzzle.GetInputArray())
 	maze := buildMaze(targetX+mazeHangover, targetY+mazeHangover)
-
-	path := shortestPathToTarget(maze, tools.NewGridToggle(), 1, 1)
+	path := maze.GetPathAStar(tools.Coordinate{X: 1, Y: 1}, tools.Coordinate{X: targetX, Y: targetY}, false)
 	printMaze(maze, path)
 
-	return path.GetOnCount() - 1
+	return len(path) - 1
 }
 
 func Part2(puzzle tools.AoCPuzzle) interface{} {