feat(tazjin/aoc2023): day 1 solution r/7104

The second task was very annoying because you had to guess the actual
rules (overlapping words), as they're not explained correctly in the
task. My solution hardcodes those cases.

Change-Id: Idf24579a78a1b8ede368504d3ff0c58c9978f069
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10183
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: tazjin <tazjin@tvl.su>

1 files changed, 52 insertions, 0 deletions

diff --git a/users/tazjin/aoc2023/day1.el b/users/tazjin/aoc2023/day1.el
new file mode 100644
index 0000000000..b1a7faff02
--- /dev/null
+++ b/users/tazjin/aoc2023/day1.el
@@ -0,0 +1,52 @@
+(require 's)
+(require 'f)
+
+;; task 1
+
+(defun digit-p (c)
+  (and (> c ?0)
+       (<= c ?9)))
+
+(defun aocd1-sum-values (lines)
+  (-sum
+   (-map (lambda (line)
+           (let ((digits (-filter #'digit-p (string-to-list line))))
+             (string-to-number (string (-first-item digits) (-last-item digits)))))
+         lines)))
+
+(let ((lines (s-lines (s-trim (f-read "~/Downloads/input.txt")))))
+  (aocd1-sum-values lines))
+
+;; task 2
+
+(defun replace-written-numbers (input)
+  (with-temp-buffer
+    (insert input)
+    (let ((start 1))
+      (while (< start (point-max))
+        (format-replace-strings
+         '(("oneight" . "18")
+           ("twone" . "21")
+           ("threeight" . "38")
+           ("fiveight" . "58")
+           ("sevenine" . "79")
+           ("eightwo" . "82")
+           ("eighthree" . "83")
+           ("nineight" . "98"))
+         nil start (min (+ 10 start) (point-max)))
+        (format-replace-strings
+         '(("one" . "1")
+           ("two" . "2")
+           ("three" . "3")
+           ("four" . "4")
+           ("five" . "5")
+           ("six" . "6")
+           ("seven" . "7")
+           ("eight" . "8")
+           ("nine" . "9"))
+         nil start (min (+ 5 start) (point-max)))
+        (setq start (1+ start))))
+    (buffer-string)))
+
+(let ((lines (s-lines (s-trim (f-read "~/Downloads/input.txt")))))
+  (aocd1-sum-values (-map #'replace-written-numbers lines)))