Bash: 2022/day 4 part 1

2022/day04/README.org

@@ -65,10 +65,26 @@ pairs.
 
 /In how many assignment pairs does one range fully contain the other?/
 
-To begin, [[file:4/input][get your puzzle input]].
+Your puzzle answer was =444=.
+
+The first half of this puzzle is complete! It provides one gold star: *
+
+** --- Part Two ---
+It seems like there is still quite a bit of duplicate work planned.
+Instead, the Elves would like to know the number of pairs that /overlap
+at all/.
+
+In the above example, the first two pairs (=2-4,6-8= and =2-3,4-5=)
+don't overlap, while the remaining four pairs (=5-7,7-9=, =2-8,3-7=,
+=6-6,4-6=, and =2-6,4-8=) do overlap:
+
+- =5-7,7-9= overlaps in a single section, =7=.
+- =2-8,3-7= overlaps all of the sections =3= through =7=.
+- =6-6,4-6= overlaps in a single section, =6=.
+- =2-6,4-8= overlaps in sections =4=, =5=, and =6=.
+
+So, in this example, the number of overlapping assignment pairs is =4=.
+
+/In how many assignment pairs do the ranges overlap?/
 
 Answer:
-
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2022/day04/aoc.bash

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+#
+# aoc.bash: Advent of Code 2022, day 3
+#
+# Copyright (C) 2022 Bruno Raoult ("br")
+# Licensed under the GNU General Public License v3.0 or later.
+# Some rights reserved. See COPYING.
+#
+# You should have received a copy of the GNU General Public License along with this
+# program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+#
+# SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+
+. common.bash
+
+export LANG=C
+declare -a sections
+
+parse() {
+    local -a _arr
+    local -i _tmp
+
+    while IFS=-, read -ra _arr; do
+        # arrange the two sections so that the lowest is the first
+        printf "_arr=%s\n" "${_arr[*]}"
+        if ((_arr[0] > _arr[2])); then
+            ((_tmp=_arr[0], _arr[0]=_arr[2], _arr[2]=_tmp))
+            ((_tmp=_arr[1], _arr[1]=_arr[3], _arr[3]=_tmp))
+            printf "\t->%s\n" "${_arr[*]}"
+        fi
+        sections+=("${_arr[*]}")
+    done
+    #readarray -t input
+}
+
+part1() {
+    declare -ig res=0
+    local -a _sect
+
+    for line in "${sections[@]}"; do
+        # shellcheck disable=SC2206
+        _sect=($line)
+        (( _sect[1] >= _sect[3] ||
+               (_sect[0] == _sect[2] && _sect[3] >= _sect[1]) )) && (( res++ ))
+    done
+}
+
+solve() {
+    if (($1 == 1)); then
+        part1
+    else
+        part2
+    fi
+}
+
+main "$@"
+exit 0