From 0a9585b4394bf6d69a1286f92e810818f963ccb8 Mon Sep 17 00:00:00 2001
From: Pierre Jeanjean <rhiobet@gmail.com>
Date: Thu, 16 Dec 2021 11:08:24 +0100
Subject: [PATCH] Day 16

---
 16/01.sh |  73 ++++++++++++++++++++++++++++
 16/02.sh | 142 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 215 insertions(+)
 create mode 100755 16/01.sh
 create mode 100755 16/02.sh

diff --git a/16/01.sh b/16/01.sh
new file mode 100755
index 0000000..c4652ad
--- /dev/null
+++ b/16/01.sh
@@ -0,0 +1,73 @@
+#!/bin/bash
+
+read input
+input=( $(sed 's/\(.\)/ \1 /g' <<< $input) )
+bits=()
+cursor=0
+sum_version=0
+
+for input_char in ${input[@]}; do
+  case $input_char in
+    '0') bits+=( 0 0 0 0 ) ;;
+    '1') bits+=( 0 0 0 1 ) ;;
+    '2') bits+=( 0 0 1 0 ) ;;
+    '3') bits+=( 0 0 1 1 ) ;;
+    '4') bits+=( 0 1 0 0 ) ;;
+    '5') bits+=( 0 1 0 1 ) ;;
+    '6') bits+=( 0 1 1 0 ) ;;
+    '7') bits+=( 0 1 1 1 ) ;;
+    '8') bits+=( 1 0 0 0 ) ;;
+    '9') bits+=( 1 0 0 1 ) ;;
+    'A') bits+=( 1 0 1 0 ) ;;
+    'B') bits+=( 1 0 1 1 ) ;;
+    'C') bits+=( 1 1 0 0 ) ;;
+    'D') bits+=( 1 1 0 1 ) ;;
+    'E') bits+=( 1 1 1 0 ) ;;
+    'F') bits+=( 1 1 1 1 ) ;;
+  esac
+done
+
+function parse_packet() {
+  local version=$((2#${bits[$((cursor))]}${bits[$((cursor+1))]}${bits[$((cursor+2))]}))
+  local packet_type=$((2#${bits[$((cursor+3))]}${bits[$((cursor+4))]}${bits[$((cursor+5))]}))
+  cursor=$((cursor+6))
+  case $packet_type in
+    '4')
+      local binary_value='2#'
+      local end_reached=0
+      while [ $end_reached -eq 0 ]; do
+        if [ ${bits[$cursor]} -eq 0 ]; then
+          end_reached=1
+	fi
+        cursor=$((cursor+5))
+      done
+      ;;
+
+    *)
+      local length_type=${bits[$cursor]}
+      cursor=$((cursor+1))
+      if [ $length_type -eq 0 ]; then
+	local subpackets_length_arr=${bits[@]:$cursor:15}
+        local subpackets_length=$((2#${subpackets_length_arr// /}))
+	cursor=$((cursor+15))
+        local curr_cursor=$cursor
+	while [ $cursor -lt $((curr_cursor+subpackets_length)) ]; do
+	  parse_packet
+	done
+      else
+	local subpackets_num_arr=${bits[@]:$cursor:11}
+        local subpackets_num=$((2#${subpackets_num_arr// /}))
+	local i
+	cursor=$((cursor+11))
+	for ((i=0;i<subpackets_num;i++)); do
+	  parse_packet
+	done
+      fi
+      ;;
+  esac
+  sum_version=$((sum_version+version))
+}
+
+parse_packet 
+
+echo $sum_version
diff --git a/16/02.sh b/16/02.sh
new file mode 100755
index 0000000..7b1dd5f
--- /dev/null
+++ b/16/02.sh
@@ -0,0 +1,142 @@
+#!/bin/bash
+
+read input
+input=( $(sed 's/\(.\)/ \1 /g' <<< $input) )
+bits=()
+cursor=0
+registers=()
+
+for input_char in ${input[@]}; do
+  case $input_char in
+    '0') bits+=( 0 0 0 0 ) ;;
+    '1') bits+=( 0 0 0 1 ) ;;
+    '2') bits+=( 0 0 1 0 ) ;;
+    '3') bits+=( 0 0 1 1 ) ;;
+    '4') bits+=( 0 1 0 0 ) ;;
+    '5') bits+=( 0 1 0 1 ) ;;
+    '6') bits+=( 0 1 1 0 ) ;;
+    '7') bits+=( 0 1 1 1 ) ;;
+    '8') bits+=( 1 0 0 0 ) ;;
+    '9') bits+=( 1 0 0 1 ) ;;
+    'A') bits+=( 1 0 1 0 ) ;;
+    'B') bits+=( 1 0 1 1 ) ;;
+    'C') bits+=( 1 1 0 0 ) ;;
+    'D') bits+=( 1 1 0 1 ) ;;
+    'E') bits+=( 1 1 1 0 ) ;;
+    'F') bits+=( 1 1 1 1 ) ;;
+  esac
+done
+
+function parse_packet() {
+  local version=$((2#${bits[$((cursor))]}${bits[$((cursor+1))]}${bits[$((cursor+2))]}))
+  local packet_type=$((2#${bits[$((cursor+3))]}${bits[$((cursor+4))]}${bits[$((cursor+5))]}))
+  cursor=$((cursor+6))
+  case $packet_type in
+    '4')
+      local binary_value='2#'
+      local end_reached=0
+      while [ $end_reached -eq 0 ]; do
+        if [ ${bits[$cursor]} -eq 0 ]; then
+          end_reached=1
+	fi
+        local binary_block=${bits[@]:$((cursor+1)):4}
+        binary_value=$binary_value${binary_block// /}
+        cursor=$((cursor+5))
+      done
+      registers+=( $((binary_value)) )
+      ;;
+
+    *)
+      local length_type=${bits[$cursor]}
+      cursor=$((cursor+1))
+      if [ $length_type -eq 0 ]; then
+	local subpackets_length_arr=${bits[@]:$cursor:15}
+        local subpackets_length=$((2#${subpackets_length_arr// /}))
+	cursor=$((cursor+15))
+        local curr_cursor=$cursor
+	local i
+	while [ $cursor -lt $((curr_cursor+subpackets_length)) ]; do
+	  parse_packet
+	  i=$((i+1))
+	done
+      else
+	local subpackets_num_arr=${bits[@]:$cursor:11}
+        local subpackets_num=$((2#${subpackets_num_arr// /}))
+	local i
+	cursor=$((cursor+11))
+	for ((i=0;i<subpackets_num;i++)); do
+	  parse_packet
+	done
+      fi
+      local j
+      case $packet_type in
+	'0')
+          local result=0
+	  for ((j=-1; j>=-i; j--)); do
+            result=$((result+registers[-1]))
+	    unset registers[-1]
+	  done
+	  ;;
+	'1')
+	  local result=1
+	  for ((j=-1; j>=-i; j--)); do
+            result=$((result*registers[-1]))
+	    unset registers[-1]
+	  done
+	  ;;
+	'2')
+	  local result=${registers[-1]}
+          unset registers[-1]
+	  for ((j=-2; j>=-i; j--)); do
+	    if [ ${registers[-1]} -lt $result ]; then
+              result=${registers[-1]}
+	    fi
+	    unset registers[-1]
+	  done
+	  ;;
+	'3')
+	  local result=${registers[-1]}
+          unset registers[-1]
+	  for ((j=-2; j>=-i; j--)); do
+	    if [ ${registers[-1]} -gt $result ]; then
+              result=${registers[-1]}
+	    fi
+	    unset registers[-1]
+	  done
+	  ;;
+	'5')
+	  if [ ${registers[-2]} -gt ${registers[-1]} ]; then
+	    local result=1
+	  else
+	    local result=0
+	  fi
+	  unset registers[-1]
+	  unset registers[-1]
+	  ;;
+	'6')
+	  if [ ${registers[-2]} -lt ${registers[-1]} ]; then
+	    local result=1
+	  else
+	    local result=0
+	  fi
+	  unset registers[-1]
+	  unset registers[-1]
+	  ;;
+	'7')
+	  if [ ${registers[-2]} -eq ${registers[-1]} ]; then
+	    local result=1
+	  else
+	    local result=0
+	  fi
+	  unset registers[-1]
+	  unset registers[-1]
+	  ;;
+      esac
+      registers+=( $result )
+      ;;
+  esac
+}
+
+parse_packet 
+
+echo $registers