From 2bdb340f9126ae5922280a1e0978383c5a0bfa9b Mon Sep 17 00:00:00 2001
From: Mike Vink <mike1994vink@gmail.com>
Date: Tue, 13 Dec 2022 18:41:39 +0100
Subject: hashing

---
 day13.go      | 139 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 day13.txt     |  23 ++++++++++
 hashbydata.go |  24 ++++++++++
 3 files changed, 186 insertions(+)
 create mode 100644 day13.go
 create mode 100644 day13.txt
 create mode 100644 hashbydata.go

diff --git a/day13.go b/day13.go
new file mode 100644
index 0000000..6d92ba5
--- /dev/null
+++ b/day13.go
@@ -0,0 +1,139 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+)
+
+type (
+	t     interface{}
+	empty struct{}
+)
+
+type packet struct {
+	data []t
+}
+
+func intOrList(v t) int {
+	switch v.(type) {
+	case int:
+		return 0
+	case []t:
+		return 1
+	default:
+		return -1
+	}
+}
+
+type continuation struct {
+	i    int
+	ok   bool
+	a, b []t
+}
+
+func comparePackets(p1, p2 *packet, comp func(a, b int) bool) (int, bool) {
+	var cp func(i int, ok bool, a, b []t) (int, bool)
+
+	var ctn []continuation
+	cp = func(i int, ok bool, a, b []t) (int, bool) {
+		if !ok {
+			return i, false
+		}
+		if al, bl := i >= len(a), i >= len(b); al || bl {
+			if bl && !al {
+				return i, false
+			}
+			return i, ok
+		}
+		at, bt := intOrList(a), intOrList(b)
+		if at == 1 && bt == 1 {
+		} else if at == 1 && bt == 0 {
+		} else if at == 0 && bt == 1 {
+		} else if at == 0 && bt == 0 {
+		} else {
+		}
+
+		return i, true
+	}
+	ctn = append(ctn, continuation{0, true, p1.data, p2.data})
+	for len(ctn) > 0 {
+	}
+	return cp(0, true, p1.data, p2.data)
+}
+
+func parsePacket(b []byte) *packet {
+	var parseList func(list []t, b []byte) []t
+
+	parseList = func(list []t, b []byte) []t {
+		for i := 0; i < len(b); i++ {
+			switch {
+			case b[0] == '[' && b[1] == ']':
+				list = append(list, []t{})
+				return list
+			case b[i] == '[':
+				j := 1
+				subchildren := 1
+				for subchildren > 0 {
+					if b[i+j] == '[' {
+						subchildren += 1
+					}
+					if b[i+j] == ']' {
+						subchildren = subchildren - 1
+					}
+					j++
+				}
+				list = append(list, parseList([]t{}, b[i+1:i+j-1]))
+				i = i + j
+			default:
+				j := 0
+				for ; i+j < len(b); j++ {
+					stop := false
+					switch b[i+j] {
+					case ']':
+						stop = true
+					case ',':
+						stop = true
+					}
+					if stop {
+						break
+					}
+				}
+				s := string(b[i : i+j])
+				if len(s) == 0 {
+					s = string(b[len(b)-1])
+				}
+				num, err := strconv.Atoi(s)
+				if err != nil {
+					log.Fatal("This is no a number!", i, j, s)
+				}
+				list = append(list, num)
+				i = i + j
+			}
+		}
+		return list
+	}
+
+	return &packet{data: parseList([]t{}, b[1:len(b)-1])}
+}
+
+func main() {
+	f, err := os.Open("day13.txt")
+	if err != nil {
+		log.Fatal("Could not read input file")
+	}
+
+	s := bufio.NewScanner(f)
+	packets := []*packet{}
+	for s.Scan() {
+		if len(s.Bytes()) > 0 {
+			packets = append(packets, parsePacket(s.Bytes()))
+		}
+	}
+	for i := 0; i < len(packets); i += 2 {
+		fmt.Println(packets[i])
+		fmt.Println(comparePackets(packets[i], packets[i+1], func(a, b int) bool { return a < b }))
+	}
+}
diff --git a/day13.txt b/day13.txt
new file mode 100644
index 0000000..af73fbb
--- /dev/null
+++ b/day13.txt
@@ -0,0 +1,23 @@
+[1,1,3,1,1]
+[1,1,5,1,1]
+
+[[1],[2,3,4]]
+[[1],4]
+
+[9]
+[[8,7,6]]
+
+[[4,4],4,4]
+[[4,4],4,4,4]
+
+[7,7,7,7]
+[7,7,7]
+
+[]
+[3]
+
+[[[]]]
+[[]]
+
+[1,[2,[3,[4,[5,6,7]]]],8,9]
+[1,[2,[3,[4,[5,6,0]]]],8,9]
diff --git a/hashbydata.go b/hashbydata.go
new file mode 100644
index 0000000..83874f3
--- /dev/null
+++ b/hashbydata.go
@@ -0,0 +1,24 @@
+package main
+
+import "fmt"
+
+type (
+	empty struct{}
+	t     interface{}
+	set   map[t]empty
+)
+
+func main() {
+	m := make(map[t]string)
+	fmt.Println(fmt.Sprintf("%+v", m))
+	m[struct{ x string }{x: "hello there"}] = "hello there"
+	fmt.Println(fmt.Sprintf("%+v", m))
+
+	m[struct{ x string }{x: "hello there"}] = "goodbye"
+	fmt.Println(fmt.Sprintf("%+v", m))
+
+	ptr := &struct{ x string }{x: "hello there"}
+	pv := *ptr
+	m[pv] = "ptr"
+	fmt.Println(fmt.Sprintf("%+v", m))
+}
-- 
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