add day 2; part 2 broken

2024/day02.go

@@ -0,0 +1,118 @@
+package adventoc2024
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strings"
+)
+
+type Day2 struct{}
+
+func (d Day2) Part1(r io.Reader) string {
+	s := bufio.NewScanner(r)
+	var sum int
+
+Scan:
+	for s.Scan() {
+
+		sz := strings.Count(s.Text(), " ") + 1
+
+		level := make([]int, sz)
+		levelprts := make([]any, sz)
+		for i := range levelprts {
+			levelprts[i] = &level[i]
+		}
+
+		fmt.Sscan(s.Text(), levelprts...)
+
+		increasing := level[1]-level[0] > 0
+		if increasing {
+			for i := 0; i < len(level)-1; i++ {
+				if diff := level[i+1] - level[i]; diff > 3 || diff < 1 {
+					continue Scan
+				}
+			}
+			sum++
+		} else {
+			for i := 0; i < len(level)-1; i++ {
+				if diff := level[i] - level[i+1]; diff > 3 || diff < 1 {
+					continue Scan
+				}
+			}
+			sum++
+		}
+	}
+
+	return printi(sum)
+}
+
+func (d Day2) Part2(r io.Reader) string {
+	s := bufio.NewScanner(r)
+	var sum int
+
+Scan:
+	for s.Scan() {
+
+		sz := strings.Count(s.Text(), " ") + 1
+
+		level := make([]int, sz)
+		levelprts := make([]any, sz)
+		for i := range levelprts {
+			levelprts[i] = &level[i]
+		}
+
+		fmt.Sscan(s.Text(), levelprts...)
+
+		increasing := level[1]-level[0] > 0
+		var dampened bool
+		if increasing {
+			for i := 0; i < len(level)-1; i++ {
+				if diff := level[i+1] - level[i]; !inrange(diff) {
+					if dampened {
+						continue Scan
+					}
+
+					if i+2 > len(level)-1 {
+						continue Scan
+					}
+
+					d2 := level[i+2] - level[i]
+					if !inrange(d2) {
+						continue Scan
+					}
+
+					dampened = true
+					i++
+				}
+			}
+			sum++
+		} else {
+			for i := 0; i < len(level)-1; i++ {
+				if diff := level[i] - level[i+1]; !inrange(diff) {
+					if dampened {
+						continue Scan
+					}
+
+					if i+2 > len(level)-1 {
+						continue Scan
+					}
+
+					d2 := level[i] - level[i+2]
+					if !inrange(d2) {
+						continue Scan
+					}
+
+					dampened = true
+					i++
+				}
+			}
+			sum++
+		}
+	}
+	return printi(sum)
+}
+
+func inrange(i int) bool {
+	return i < 4 && i > 0
+}