complete day 2

02-a.kts

@@ -0,0 +1,33 @@
+import java.util.Scanner
+
+val isSafelyIncreasing = { offset: Int -> offset in 1..3 }
+
+val isSafelyDecreasing = { offset: Int -> offset in (-3)..(-1) }
+
+fun isSafeRoute(levels: List<Int>): Boolean {
+    val levelOffsets = levels.foldIndexed(ArrayList<Int>()) { index, acc, i ->
+        if (index > 0) {
+            acc.add(i - levels[index - 1])
+        }
+        acc
+    }
+
+    return levelOffsets.all(isSafelyIncreasing) || levelOffsets.all(isSafelyDecreasing)
+}
+
+val scanner = Scanner(System.`in`)
+
+var safeCount = 0
+while (scanner.hasNextInt()) {
+    val line = scanner.nextLine()
+
+    val numbers = line.split(" ").map { it.toInt() }
+
+    if (isSafeRoute(numbers)) {
+        safeCount++
+    }
+}
+
+println(safeCount)
+
+

02-b.kts

@@ -0,0 +1,49 @@
+import java.util.Scanner
+
+val isSafelyIncreasing = { offset: Int -> offset in 1..3 }
+
+val isSafelyDecreasing = { offset: Int -> offset in (-3)..(-1) }
+
+fun isSafeRoute(levels: List<Int>): Boolean {
+    val levelOffsets = levels.foldIndexed(ArrayList<Int>()) { index, acc, i ->
+        if (index > 0) {
+            acc.add(i - levels[index - 1])
+        }
+        acc
+    }
+
+    return (levelOffsets.all(isSafelyIncreasing) || levelOffsets.all(isSafelyDecreasing))
+
+}
+
+fun isSafeRouteTolerated(levels: List<Int>): Boolean {
+    if (isSafeRoute(levels)) {
+        return true
+    }
+
+    for (skipPos in levels.indices) {
+        val skippedList = levels.slice((0)..<skipPos) + levels.slice((skipPos+1)..levels.lastIndex)
+        if (isSafeRoute(skippedList)) {
+            return true
+        }
+    }
+
+    return false
+}
+
+val scanner = Scanner(System.`in`)
+
+var safeCount = 0
+while (scanner.hasNextInt()) {
+    val line = scanner.nextLine()
+
+    val numbers = line.split(" ").map { it.toInt() }
+
+    if (isSafeRouteTolerated(numbers)) {
+        safeCount++
+    }
+}
+
+println(safeCount)
+
+