package main

import (
	"fmt"
)

// https://adventofcode.com/2024/day/2
// 7 6 4 2 1
// 1 2 7 8 9
// 9 7 6 2 1
// 1 3 2 4 5
// 8 6 4 4 1
// 1 3 6 7 9
var reports = [][]int{{7,6,4,2,1},
	{1,2,7,8,9},
	{9,7,6,2,1},
	{1,3,2,4,5},
	{8,6,4,4,1},
	{1,3,6,7,9}}

func abs(num int) int {
	if (num < 0) {
		return -num
	} else {
		return num
	}
}

// lvl == level
func compareLevels(report []int) (bool) {
	var isReportSafe bool = false
	var incrOrDecr   bool = report[1] > report[0] // incr: true | decr: false
	for i := 0; i < len(report)-1; i++ {
		var lvlDifference int = abs(report[i]-report[i+1])

		if lvlDifference > 3 || lvlDifference == 0 {
			return false
		} else if incrOrDecr != (report[i+1] > report[i]) {
			return false
		} else {
			isReportSafe = true
			continue
		}
	}
	return isReportSafe
}

func main() {
	var safeReportCount int

	for _, report := range reports {
		isReportSafe := compareLevels(report)
		if isReportSafe {
			safeReportCount++
		}
	}

	fmt.Printf("List of reports: %v\n", reports)
	fmt.Printf("Number of safe reports: %v\n", safeReportCount)
}