Add driver, license and Readme.

driver.sh

@@ -0,0 +1,65 @@
+#!/bin/sh
+set -eu
+
+# Find the source directory
+cwd="$(pwd)"
+cd "$(dirname "$0")"
+srcdir="$(pwd)"
+cd "${cwd}"
+
+# Parse command line options
+if [ $# -ne 4 ]; then
+    echo "Usage: $0 <year> <day> <puzzle> <input-file>" >&2
+    exit 1
+fi
+
+# Parse and validate command line options"
+year="$1"
+day="$2"
+num="$3"
+input="$4"
+
+if [ ! -d "${srcdir}/${year}" ]; then
+  echo "Year of puzzles ${year} does not exist" >&2
+  exit 2
+fi
+
+if [ ${#day} -eq 1 ]; then
+    day="0${day}"
+fi
+
+if [ ${#num} -eq 1 ]; then
+    num="0${num}"
+fi
+
+puzzle_src="${srcdir}/${year}/puzzle-${day}-${num}.cc"
+puzzle="puzzle-${year}-${day}-${num}"
+exe="build/puzzle-${year}-${day}-${num}"
+
+if [ ! -e "${puzzle_src}" ]; then
+    echo "Unable to find puzzle sources for ${year}-12-${day} number ${num}" >&2
+    exit 2
+fi
+
+# Rebuild the executable we want to run.
+if [ ! -d "build" ]; then
+    opts=
+    if [ "$(uname -s)" == "Darwin" ]; then
+      if [ "$(uname -m)" == "arm64" ]; then
+        opts="-DOPENSSL_ROOT_DIR=/opt/homebrew/opt/openssl"
+      else
+        opts="-DOPENSSL_ROOT_DIR=/usr/local/opt/openssl"
+      fi
+    fi
+
+    cmake -Bbuild -S "${srcdir}" ${opts}
+fi
+cmake --build build --target "${puzzle}"
+
+# And run the executable - using the driver if necessary.
+driver="${srcdir}/${year}/driver-${day}-${num}.sh"
+if [ -e "${driver}" ]; then
+    sh "${driver}" "${exe}" "${input}"
+else
+    "${exe}" <"${input}"
+fi