[bash] Solve Day 1

bash/day1.sh

@@ -0,0 +1,102 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+firstDigits() {
+    sed 's|^[^0-9]*\([0-9]\).*|\1|'
+}
+
+lastDigits() {
+    sed 's|^.*\([0-9]\)[^0-9]*$|\1|'
+}
+
+sumTensDigits() {
+    echo $(("$(xargs -I '{}' echo '{} * 10 +') 0"))
+}
+
+sumOnesDigits() {
+    echo $(("$(xargs -I '{}' echo '{} +') 0"))
+}
+
+detectDigits() {
+    sed '
+         s|zero|0|g;
+
+         s|twone|2|g;
+         s|one|1|g;
+
+         s|eightwo|8|g;
+         s|two|2|g;
+
+         s|eighthree|8|g;
+         s|three|3|g;
+
+         s|four|4|g;
+         s|five|5|g;
+         s|six|6|g;
+         s|seven|7|g;
+
+         s|nineight|9|g;
+         s|eight|8|g;
+
+         s|nine|9|g
+         '
+}
+
+detectReverseDigits() {
+    sed '
+         s|enorez|1|g
+         s|orez|0|g;
+
+         s|thgieno|8|g;
+         s|eno|1|g;
+
+         s|owt|2|g;
+
+         s|thgieerht|8|g;
+         s|eerht|3|g;
+
+         s|ruof|4|g;
+
+         s|thgievif|8|g;
+         s|evif|5|g;
+
+         s|xis|6|g;
+
+         s|enineves|9|g
+         s|neves|7|g;
+
+         s|thgie|8|g;
+
+         s|enin|9|g
+         '
+}
+
+part1 () {
+    local input tensSum onesSum
+    input=$(cat)
+    tensSum=$(<<< "$input" firstDigits | sumTensDigits)
+    onesSum=$(<<< "$input" lastDigits | sumOnesDigits)
+    echo $(("$tensSum + $onesSum"))
+}
+
+part2 () {
+    local input tensSum onesSum
+    input=$(cat)
+    tensSum=$(<<< "$input" detectDigits | firstDigits | sumTensDigits)
+    onesSum=$(<<< "$input" rev | detectReverseDigits | firstDigits | sumOnesDigits)
+    echo $(("$tensSum + $onesSum"))
+}
+
+main () {
+    local input part1Answer part2Answer
+    input=$(cat)
+
+    part1Answer=$(part1 <<< "$input")
+    echo "Part 1 Answer: $part1Answer"
+
+    part2Answer=$(part2 <<< "$input")
+    echo "Part 2 Answer: $part2Answer"
+}
+
+main

bash/main.sh

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+#!/usr/bin/env bash
+
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+
+case "$1" in
+    "day1")
+        "$SCRIPT_DIR/day1.sh"
+        ;;
+    *)
+        echo "Invalid day"
+        exit 1
+        ;;
+esac