day02

day02.sh

@@ -0,0 +1,58 @@
+#!/usr/bin/env bash
+unset PATH; readonly PATH
+source ./utils/main.sh
+source ./utils/array.sh
+
+is_report_valid() {
+  local report=() current_sign='' i=0
+  read -ra report <<< "$1"
+  
+  for (( i = 0; i < ${#report[@]} - 1; i++ )); do
+    local a="${report[i]}" b="${report[i+1]}" diff='' sign=''
+    diff="$((a - b))"
+    ((${diff#-} >= 1 && ${diff#-} <= 3)) || return 1
+
+    if ((diff > 0)); then
+      sign='+'
+    else
+      sign='-'
+    fi
+
+    [[ -z "${current_sign:-}" ]] && current_sign="$sign"
+    [[ "$sign" != "$current_sign" ]] && return 1
+  done
+
+  return 0
+}
+
+p1() {
+  local input="$1" result=0 line=''
+
+  while read -r line; do
+    is_report_valid "$line" && ((result++))
+  done <<< "$input"
+
+  printf '%d' "$result"
+}
+
+p2() {
+  local input="$1" result=0 line=''
+
+  while read -r line; do
+    local original_report
+    read -ra original_report <<< "$line"
+
+    is_report_valid "$line" && ((result++)) && continue
+
+    for (( i = 0; i < ${#original_report[@]}; i++ )); do
+      local report
+      report=("${original_report[@]::"$i"}" "${original_report[@]:"$((i+1))"}")
+
+      is_report_valid "${report[*]}" && ((result++)) && continue 2
+    done
+  done <<< "$input"
+
+  printf '%d' "$result"
+}
+
+main "$@"