<?xml version="1.0" encoding="UTF-8"?>

<module type="JAVA_MODULE" version="4">

<component name="NewModuleRootManager" inherit-compiler-output="true">

<exclude-output />

<content url="file://$MODULE_DIR$">

<sourceFolder url="file://$MODULE_DIR$/resources" type="java-resource" />

<sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />

<sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />

<sourceFolder url="file://$MODULE_DIR$/testResources" type="java-test-resource" />

</content>

<orderEntry type="inheritedJdk" />

<orderEntry type="sourceFolder" forTests="false" />

<orderEntry type="library" name="KotlinJavaRuntime" level="project" />

</component>

</module>

import java.io.File

import kotlin.math.max

fun main(args: Array<String>) {

println("AOC 2024, Day 4, Part 2 starting!!!!")

val theData = WordSearchData()

var yPosition = 0

File(args[0]).forEachLine {

var xPosition = 0

for(c in it.toCharArray()) {

val newWordSearchCharacter = WordSearchCharacter(c, xPosition, yPosition)

theData.characters.add(newWordSearchCharacter)

xPosition++

}

theData.maxX = xPosition

yPosition++

}

theData.maxY = yPosition

val answer = theData.searchForXmas()

println("Word search grid: ${theData.maxX} x ${theData.maxY}")

println("Number of matches: $answer")

println("AOC 2024, Day 4, Part 2 completed!!!")

}

class WordSearchData {

val characters = ArrayList<WordSearchCharacter>()

var maxX: Int = 0

set(value) {

field = max(field, value)

}

var maxY: Int = 0

set(value) {

field = max(field, value)

}

enum class Direction {

UP_LEFT, UP, UP_RIGHT, LEFT, RIGHT, DOWN_LEFT, DOWN, DOWN_RIGHT

}

fun searchForXmas(): Int {

var matches = 0

// All characters in word search space

for (wordSearchCharacter in characters) {

// Look for matches to on characters XMAS

if ((wordSearchCharacter.theChar == 'A') && searchForXMAS(wordSearchCharacter)) {

println("Found X of MAS at ${wordSearchCharacter.xPosition}, ${wordSearchCharacter.yPosition}")

matches++

}

}

return matches

}

private fun searchForXMAS(character: WordSearchCharacter): Boolean {

return checkPattern1(character) || checkPattern2(character) || checkPattern3(character) || checkPattern4(character)

}

// Pattern 1

// M . M

// . A .

// S . S

private fun checkPattern1(character: WordSearchCharacter):Boolean {

return searchForMAS(character, 'M', Direction.UP_LEFT, 1) &&

searchForMAS(character, 'M', Direction.UP_RIGHT, 1) &&

searchForMAS(character, 'S', Direction.DOWN_LEFT, 1) &&

searchForMAS(character, 'S', Direction.DOWN_RIGHT, 1)

}

// Pattern 2

// M . S

// . A .

// M . S

private fun checkPattern2(character: WordSearchCharacter):Boolean {

return searchForMAS(character, 'M', Direction.UP_LEFT, 1) &&

searchForMAS(character, 'S', Direction.UP_RIGHT, 1) &&

searchForMAS(character, 'M', Direction.DOWN_LEFT, 1) &&

searchForMAS(character, 'S', Direction.DOWN_RIGHT, 1)

}

// Pattern 3

// S . S

// . A .

// M . M

private fun checkPattern3(character: WordSearchCharacter):Boolean {

return searchForMAS(character, 'S', Direction.UP_LEFT, 1) &&

searchForMAS(character, 'S', Direction.UP_RIGHT, 1) &&

searchForMAS(character, 'M', Direction.DOWN_LEFT, 1) &&

searchForMAS(character, 'M', Direction.DOWN_RIGHT, 1)

}

// Pattern 4

// S . M

// . A .

// S . M

private fun checkPattern4(character: WordSearchCharacter):Boolean {

return searchForMAS(character, 'S', Direction.UP_LEFT, 1) &&

searchForMAS(character, 'M', Direction.UP_RIGHT, 1) &&

searchForMAS(character, 'S', Direction.DOWN_LEFT, 1) &&

searchForMAS(character, 'M', Direction.DOWN_RIGHT, 1)

}

private fun searchForMAS(character: WordSearchCharacter, lookFor: Char, direction: Direction, step: Int): Boolean {

var nextX = character.xPosition

var nextY = character.yPosition

when (direction) {

// search up left : x - 1, y - 1

Direction.UP_LEFT -> {

nextX -= step

nextY -= step

}

// search up : x, y - 1

Direction.UP -> {

nextY -= step

}

// search up right : x + 1, y - 1

Direction.UP_RIGHT -> {

nextX += step

nextY -= step

}

// search left : x - 1, y

Direction.LEFT -> {

nextX -= step

}

// search right : x + 1, y

Direction.RIGHT -> {

nextX += step

}

// search down left : x - 1, y + 1

Direction.DOWN_LEFT -> {

nextX -= step

nextY += step

}

// search down : x, y + 1

Direction.DOWN -> {

nextY += step

}

// search down right: x + 1, y + 1

Direction.DOWN_RIGHT -> {

nextX += step

nextY += step

}

}

if (positionCheck(nextX, nextY)) {

val nextChar =

characters.find { allCharacters -> allCharacters.xPosition == nextX && allCharacters.yPosition == nextY }

return nextChar?.theChar == lookFor

}

// If code arrives here, then false

return false

}

private fun positionCheck(x: Int, y: Int): Boolean {

if ((x < 0) || (y < 0)) return false

if ((x > maxX) || (y > maxY)) return false

return true

}

}

data class WordSearchCharacter (val theChar:Char, val xPosition:Int, val yPosition:Int)