Added solution for Day 5 (Part 1)

src/Day05.kt

@@ -0,0 +1,43 @@
+import kotlin.math.max
+import kotlin.math.min
+
+fun main() {
+    fun part1(input: List<String>): Int {
+
+        val field = Array(1000) { IntArray(1000) }
+        for (line in input) {
+            val (x1, y1, x2, y2) = line.split(",", " -> ").map { it.toInt() }
+            if (x1 == x2) {
+                val yMin = min(y1, y2)
+                val yMax = max(y1, y2)
+                for (y in yMin..yMax)
+                    field[x1][y] += 1
+            } else if (y1 == y2) {
+                val xMin = min(x1, x2)
+                val xMax = max(x1, x2)
+                for (x in xMin..xMax)
+                    field[x][y1] += 1
+            }
+        }
+
+        var dangerous = 0
+        for (x in 0..field.lastIndex) {
+            for (y in 0..field[0].lastIndex) {
+                if (field[x][y] > 1) {
+                    dangerous += 1
+                }
+            }
+        }
+        return dangerous
+    }
+
+    fun part2(input: List<String>): Int {
+        return 0
+    }
+
+    val input = readInput("Day05")
+    check(part1(readInput("Day05_test")) == 5)
+
+    println(part1(input))
+    println(part2(input))
+}