From b2f39abd9347823a66dc5c6af78cb4cc9aec388f Mon Sep 17 00:00:00 2001
From: Luke Else <mail@luke-else.co.uk>
Date: Fri, 17 Dec 2021 19:11:20 +0000
Subject: [PATCH] day 16a complete

after taking up the iterative approach and sorting out all of the little bugs I was finally able to get the right value
---
 day16/16b/main.go | 155 ++++++++++++++++++++++++----------------------
 day16/testInput   |   2 +-
 2 files changed, 83 insertions(+), 74 deletions(-)

diff --git a/day16/16b/main.go b/day16/16b/main.go
index 64520a1..330f161 100644
--- a/day16/16b/main.go
+++ b/day16/16b/main.go
@@ -9,87 +9,95 @@ import (
 )
 
 func main() {
-	//content := returnContent("../input")
-	content := returnContent("../testInput")
+	content := returnContent("../input")
+	//content := returnContent("../testInput")
 
 	binary := shared.HexToBinary(content)
 
 	pointer := 0
-	version := 0
-	typeID := 0
-	lengthTypeID := "0"
-	length := 11
-	values := []int{}
 
-	answer := 0
-
-	for pointer < len(binary)-6 {
-		//Get version from first 3 Bits
-		current := ""
-		current = binary[pointer : pointer+3]
-		version += shared.BinaryToInteger(&current)
-		pointer += 3
-
-		//determine packet type ID from next 2 bits
-		current = ""
-		current = binary[pointer : pointer+3]
-		typeID = shared.BinaryToInteger(&current)
-		pointer += 3
-
-		if typeID == 4 {
-			//literal value
-			value := ""
-			for {
-				//continue adding the 4 bit values while the packets continue
-				pointer++
-				value += binary[pointer : pointer+4]
-				pointer += 4
-				if binary[pointer-5] == '0' {
-					break
-				}
-			}
-			answer = shared.BinaryToInteger(&value)
-
-		} else {
-			//operator value
-			//find the lenth of the subpackets definition
-			lengthTypeID = string(binary[pointer])
-
-			if lengthTypeID == "0" {
-				length = 15
-			} //default = 11
-			pointer++
-
-			//subpacket length value
-			temp := binary[pointer : pointer+length]
-			length = shared.BinaryToInteger(&temp)
-			fmt.Println(length, lengthTypeID)
-
-			pointer += length
-
-			//assert into values based on typeID (0 = total length, 1 = )
-			if lengthTypeID == "1" {
-				//add the series of 11 bit numbers
-				for i := 0; i < length; i++ {
-					packetString := binary[pointer : pointer+11]
-					values = append(values, shared.BinaryToInteger(&packetString))
-					pointer += 11
-				}
-				fmt.Println(values)
-			} else {
-				fmt.Println("here")
-				//add the series of ... bit numbers
-			}
-
-		}
-	}
+	answer := SeparatePackets(&binary, &pointer)
 
 	fmt.Println(answer)
 
 }
 
-func ComputePackets(version int, typeID int, values []int) (answer int) {
+func SeparatePackets(binary *string, pointer *int) (packetValue int) {
+	version := 0
+	typeID := 0
+	lengthTypeID := "0"
+	length := 11
+	subPacketValues := []int{}
+
+	//Get version from first 3 Bits
+	current := ""
+	current = (*binary)[*pointer : *pointer+3]
+	version += shared.BinaryToInteger(&current)
+	*pointer += 3
+
+	//determine packet type ID from next 2 bits
+	current = ""
+	current = (*binary)[*pointer : *pointer+3]
+	typeID = shared.BinaryToInteger(&current)
+	*pointer += 3
+
+	if typeID == 4 {
+		//literal value
+		value := ""
+		for {
+			//continue adding the 4 bit values while the packets continue
+			*pointer++
+			value += (*binary)[*pointer : *pointer+4]
+			*pointer += 4
+			if (*binary)[*pointer-5] == '0' {
+				break
+			}
+		}
+		packetValue = shared.BinaryToInteger(&value)
+		return
+
+	} else {
+		//operator value
+		//find the lenth of the subpackets definition
+		lengthTypeID = string((*binary)[*pointer])
+		if lengthTypeID == "0" {
+			length = 15
+		} //default = 11
+		*pointer++
+
+		//subpacket length value
+		temp := (*binary)[*pointer : *pointer+length]
+		subLength := shared.BinaryToInteger(&temp)
+		*pointer += length
+
+		//assert into values based on typeID (0 = total length, 1 = )
+		if lengthTypeID == "1" {
+			//add the series of 11 bit numbers
+			for i := 0; i < subLength; i++ {
+				//packetString := (*binary)[*pointer : *pointer+11]
+				subPacketValues = append(subPacketValues, SeparatePackets(binary, pointer))
+			}
+			packetValue = ComputePackets(typeID, subPacketValues)
+		} else {
+			//add the series of ... bit numbers
+			intialPointerVal := *pointer
+			for {
+				if *pointer-intialPointerVal < subLength {
+					subPacketValues = append(subPacketValues, SeparatePackets(binary, pointer))
+				} else {
+					break
+				}
+			}
+			packetValue = ComputePackets(typeID, subPacketValues)
+		}
+
+	}
+	return
+}
+
+func ComputePackets(typeID int, values []int) (answer int) {
 	answer = 0
+
 	switch typeID {
 	case 0:
 		//sum
@@ -98,15 +106,16 @@ func ComputePackets(version int, typeID int, values []int) (answer int) {
 		}
 	case 1:
 		//product
+		answer = 1
 		for _, value := range values {
 			answer = answer * value
 		}
 	case 2:
 		//min
-		min := math.MaxInt
+		answer = math.MaxInt
 		for _, value := range values {
-			if value < min {
-				min = value
+			if value < answer {
+				answer = value
 			}
 		}
 	case 3:
diff --git a/day16/testInput b/day16/testInput
index 7560cdf..6638168 100644
--- a/day16/testInput
+++ b/day16/testInput
@@ -1 +1 @@
-EE00D40C823060
\ No newline at end of file
+880086C3E88112
\ No newline at end of file