day 5

Author: cgsdev0

2024/day5/p1.sh

@@ -0,0 +1,64 @@
+#!/bin/bash
+
+FILE="$1"
+
+declare -A deps
+
+parse_rule() {
+  first="${1%%|*}"
+  second="${1##*|}"
+  if [[ -n "${deps[$second]}" ]]; then
+    first="${deps[$second]} $first"
+  fi
+  deps[$second]="$first"
+}
+
+split() {
+   # Usage: split "string" "delimiter"
+   IFS=$'\n' read -d "" -ra arr <<< "${1//$2/$'\n'}"
+}
+
+parse_update() {
+  local -a arr
+  local INVALID
+  local -a violations
+  split "$1" ,
+  local -a pages=("${arr[@]}")
+  for page in "${pages[@]}"; do
+    split "${deps[$page]}" ' '
+    for v in "${violations[@]}"; do
+      if [[ "$v" == "$page" ]]; then
+        INVALID=yes
+      fi
+    done
+    violations+=("${arr[@]}")
+  done
+  [[ -z "$INVALID" ]] && echo "${pages[@]}"
+}
+
+middle() {
+  local line
+  local -a arr
+  while IFS= read -r line; do
+    split "$line" ' '
+    LEN="${#arr[@]}"
+    ((LEN/=2))
+    echo ${arr["$LEN"]}
+  done
+}
+
+while IFS= read -r line; do
+  if [[ "$line" == "" ]]; then
+    section=2
+    continue
+  fi
+
+  if [[ $section -eq 2 ]]; then
+    parse_update "$line"
+  else
+    parse_rule "$line"
+  fi
+done < "$FILE" \
+  | middle \
+  | paste -sd+ \
+  | bc

2024/day5/p2.sh

@@ -0,0 +1,70 @@
+#!/bin/bash
+
+FILE="$1"
+
+declare -A deps
+
+parse_rule() {
+  first="${1%%|*}"
+  second="${1##*|}"
+  if [[ -n "${deps[$second]}" ]]; then
+    first="${deps[$second]} $first"
+  fi
+  deps[$second]="$first"
+}
+
+split() {
+   # Usage: split "string" "delimiter"
+   IFS=$'\n' read -d "" -ra arr <<< "${1//$2/$'\n'}"
+}
+
+parse_update() {
+  local -a arr
+  local INVALID
+  local -a violations
+  split "$1" ,
+  local -a pages=("${arr[@]}")
+  local PAGES="${#pages[@]}"
+  for ((i=0; i<PAGES; i++)); do
+    page="${pages[$i]}"
+    split "${deps[$page]}" ' '
+    for v in "${violations[@]}"; do
+      if [[ "$v" == "$page" ]]; then
+        INVALID=yes
+        pages[$i]="${pages[$((i-1))]}"
+        pages[$((i-1))]=$page
+        i=0
+        violations=()
+        break
+      fi
+    done
+    violations+=("${arr[@]}")
+  done
+  [[ -n "$INVALID" ]] && echo "${pages[@]}"
+}
+
+middle() {
+  local line
+  local -a arr
+  while IFS= read -r line; do
+    split "$line" ' '
+    LEN="${#arr[@]}"
+    ((LEN/=2))
+    echo ${arr["$LEN"]}
+  done
+}
+
+while IFS= read -r line; do
+  if [[ "$line" == "" ]]; then
+    section=2
+  fi
+
+  if [[ $section -eq 2 ]]; then
+    parse_update "$line"
+  else
+    parse_rule "$line"
+  fi
+done < "$FILE" \
+  | middle \
+  | paste -sd+ \
+  | bc