2024 day 2 part 2

2024/day-02/main.go

@@ -6,12 +6,13 @@ import (
 	"log"
 	"math"
 	"os"
+	// "slices"
 	"strconv"
 	"strings"
 )
 
 func main() {
-	file, err := os.Open("./input_test.txt")
+	file, err := os.Open("./input.txt")
 	if err != nil {
 		log.Fatalf("failed to open file: %s\n", err)
 	}
@@ -19,10 +20,9 @@ func main() {
 	s := bufio.NewScanner(file)
 
 	result1 := 0
-	line := 0
+	result2 := 0
 
 	for s.Scan() {
-		line++
 		t := s.Text()
 		strs := strings.Split(t, " ")
 		var ints = []int{}
@@ -35,49 +35,79 @@ func main() {
 			ints = append(ints, j)
 		}
 
-		var prev int
-		var current int
-		var isIncreasing bool
-		isSafe := true
-		fcount := 0
+		safe := checkSafe(ints)
 
-		for idx, num := range ints {
-			current = num
-			if idx == 0 {
-				prev = num
-				continue
-			}
-			if prev == current {
-				isSafe = false
-				fcount++
-				break
-			}
-			if idx == 1 {
-				isIncreasing = (prev < current)
-			}
-			diff := int(math.Abs(float64(prev) - float64(current)))
-
-			if diff < 1 || diff > 3 {
-				isSafe = false
-			}
-			if isIncreasing && (prev > current) {
-				isSafe = false
-			}
-			if !isIncreasing && (prev < current) {
-				isSafe = false
-			}
-
-			fmt.Printf("line: %d\tidx: %d\tprev: %d\tcurr: %d\tincr: %t\tdiff: %d\tfcount: %d\n", idx, line, prev, current, isIncreasing, diff, fcount)
-			prev = num
-		}
-
-		if isSafe {
+		if safe {
 			result1++
-		}
-		if fcount <= 1 {
 			result2++
+		} else {
+			for idxRemove := 0; idxRemove < len(ints); idxRemove++ {
+				var new_ints []int
+
+				for idx, i := range ints {
+					if idx == idxRemove { continue }
+					new_ints = append(new_ints, i)
+				}
+
+				safe := checkSafe(new_ints)
+
+				if safe {
+					result2++
+					break
+				}
+			}
 		}
 	}
 
 	fmt.Println("Result1: ", result1)
+	fmt.Println("Result2: ", result2)
+}
+
+func checkSafe(nums []int) bool {
+	var prev int
+	var current int
+	var isIncreasing bool
+	isSafe := true
+	firstFailedIdx := -1
+
+	for idx, num := range nums {
+		current = num
+		if idx == 0 {
+			prev = num
+			continue
+		}
+		if prev == current {
+			if firstFailedIdx == -1 {
+				firstFailedIdx = idx
+			}
+			isSafe = false
+			break
+		}
+		if idx == 1 {
+			isIncreasing = (prev < current)
+		}
+		diff := int(math.Abs(float64(prev) - float64(current)))
+
+		if diff < 1 || diff > 3 {
+			if firstFailedIdx == -1 {
+				firstFailedIdx = idx
+			}
+			isSafe = false
+		}
+		if isIncreasing && (prev > current) {
+			if firstFailedIdx == -1 {
+				firstFailedIdx = idx
+			}
+			isSafe = false
+		}
+		if !isIncreasing && (prev < current) {
+			if firstFailedIdx == -1 {
+				firstFailedIdx = idx
+			}
+			isSafe = false
+		}
+
+		prev = num
+	}
+	return isSafe
 }