2024 Day 2 (vlang#69)

Author: JalonSolov

2024/02/JalonSolov.v

@@ -0,0 +1,66 @@
+import math
+import os
+
+lines := os.read_lines('reports.input')!
+
+mut safe_reports := 0
+mut dampened_safe_reports := 0
+mut val := 0
+mut abs_val := 0
+
+for line in lines {
+	mut all_safe := true
+	mut bad_levels := 0
+	reps := line.split(' ').map(it.int())
+
+	mut desc := (reps[0] - reps[1]) > 0
+
+	for level_idx in 0 .. reps.len - 1 {
+		val = reps[level_idx] - reps[level_idx + 1]
+		abs_val = math.abs(val)
+		if (val > 0) != desc || abs_val < 1 || abs_val > 3 {
+			all_safe = false
+			bad_levels++
+			match level_idx {
+				// if the first problem was at the start of the line,
+				// re-do the `desc` var in case the direction changes
+				0 {
+					desc = (reps[1] - reps[2]) > 0
+					continue
+				}
+				// if the first problem is the 2nd level, recalculate
+				// desc starting from here, just in case
+				1 {
+					desc = (reps[1] - reps[2]) > 0
+				}
+				// if the problem was on the last 2 levels, no need
+				// to worry about anything else - if that was the only
+				// problem, we still have a dampened report
+				reps.len - 2 {
+					break
+				}
+				// otherwise, try checking around the error point
+				else {
+					desc = (reps[level_idx - 1] - reps[level_idx + 1]) > 0
+					val = reps[level_idx - 1] - reps[level_idx + 1]
+					abs_val = math.abs(val)
+					if (val > 0) != desc || abs_val < 1 || abs_val > 3 {
+						bad_levels++
+						break
+					}
+				}
+			}
+		}
+	}
+
+	if all_safe == true {
+		safe_reports++
+	}
+
+	if bad_levels < 2 {
+		dampened_safe_reports++
+	}
+}
+
+println('Part 1: ${safe_reports}')
+println('Part 2: ${dampened_safe_reports}')

known/2024/02/JalonSolov.out

@@ -0,0 +1,2 @@
+Part 1: 2
+Part 2: 4