AOC - Day 5

Author: cortinico

src/main/java/Exercise5-part2.kt

@@ -0,0 +1,17 @@
+fun main() {
+ val input = object {}.javaClass.getResource("input-5.txt").readText().split('\n')
+
+ val ids = input.map {
+ val row = findBinary(128, it.substring(0, 7))
+ val column = findBinary(8, it.substring(7))
+ (row * 8) + column
+ }.sorted()
+
+ ids.forEachIndexed { index, id ->
+ if (index != 0 && index != ids.size - 1 && ids[index] == ids[index + 1] - 2) {
+ println(id + 1)
+ return
+ }
+ }
+}
+

src/main/java/Exercise5.kt

@@ -0,0 +1,24 @@
+fun main() {
+ val input = object {}.javaClass.getResource("input-5.txt").readText().split('\n')
+
+ input.map {
+ val row = findBinary(128, it.substring(0, 7))
+ val column = findBinary(8, it.substring(7))
+ (row * 8) + column
+ }.maxOrNull().also(::println)
+}
+
+fun findBinary(max: Int, key: String): Int {
+ var l = 0
+ var r = max
+ var idx = 0
+ while (idx < key.length) {
+ when (key[idx]) {
+ 'F', 'L' -> r = (l+r)/2
+ 'B', 'R' -> l = (l+r)/2
+ }
+ idx++
+ }
+ return l
+}
+