day 3 puzzle 1

2023-12-03 10:56:47 +01:00
parent 8cbe1a8f52
commit 548fea505d
3 changed files with 106 additions and 0 deletions
--- a/src/day3/Puzzle1.scala
+++ b/src/day3/Puzzle1.scala
@@ -0,0 +1,87 @@
+package day3
+
+import scala.io.{BufferedSource, Source}
+
+object Puzzle1 {
+  val OFFSETS: Array[Array[Int]] = Array(
+    Array(-1,-1), Array( 0,-1), Array( 1,-1),
+    Array(-1, 0),               Array( 1, 0),
+    Array(-1, 1), Array( 0, 1), Array( 1, 1)
+  )
+  var width = 0
+  var height = 0
+
+  var schematic: Array[Array[Char]] = Array.empty
+  def loadInput(path: String): Unit = {
+    val source: BufferedSource = Source.fromFile(path)
+    val lines: Array[String] = source.getLines().toArray
+    height = lines.length
+    width = if (height == 0) 0 else lines(0).length
+    schematic = new Array(height)
+
+    var i = 0
+    for (line: String <- lines) {
+      schematic(i) = line.split("").map(s => s(0))
+      i += 1
+    }
+
+    source.close()
+  }
+
+  def getNumber(sx: Int, sy: Int): String = {
+    var x: Int = sx
+    var number: String = ""
+    var c: Char = schematic(sy)(sx)
+    do {
+      number += c
+      x += 1
+      if (x < width) c = schematic(sy)(x)
+    } while ('0' <= c && c <= '9' && x < width)
+    return number
+  }
+
+  def isPartNumber(sx: Int, sy: Int, len: Int): Boolean = {
+    for (x: Int <- sx until sx+len) {
+      for (offset: Array[Int] <- OFFSETS) {
+        val x2: Int =  x + offset(0)
+        val y2: Int = sy + offset(1)
+        if (0 <= x2 && x2 < width && 0 <= y2 && y2 < height) {
+          val c: Char = schematic(y2)(x2)
+          if (c != '.' && (c < '0' || c > '9')) {
+            return true
+          }
+        }
+      }
+    }
+    return false
+  }
+
+  def solve(path: String): Int = {
+    loadInput(path)
+
+    var sum: Int = 0
+    var y: Int = 0
+    var x: Int = 0
+
+    while (y < schematic.length) {
+      while (x < schematic(y).length) {
+        val c: Char = schematic(y)(x)
+        if ('0' <= c && c <= '9') {
+          val number: String = getNumber(x, y)
+          if (isPartNumber(x, y, number.length)) {
+            sum += number.toInt
+            x += number.length - 1
+          }
+        }
+        x += 1
+      }
+      y += 1
+      x = 0
+    }
+    return sum
+  }
+  def main(args: Array[String]): Unit = {
+    val solution: Int = solve("res/day3/input1.txt")
+    println(solution)
+  }
+}