1 files changed, 45 insertions, 0 deletions
diff --git a/2022/Day02/part-two.cl b/2022/Day02/part-two.cl
new file mode 100644
index 0000000..40090e2
--- /dev/null
+++ b/2022/Day02/part-two.cl
@@ -0,0 +1,45 @@
+(defvar *prog-input*)
+
+(let ((ui (read-line)))
+  (if (equal ui "")
+    (setq *prog-input* *standard-input*)
+    (setq *prog-input* (open ui))))
+
+(let
+  ((cal (read-line *prog-input* NIL)) (total-score 0)
+   (your-rps '(#\0 #\X #\Y #\Z)) (enemy-rps '(#\0 #\A #\B #\C))
+   (cy-rps 0) (ce-rps 0))
+
+  (loop until (or (equal cal "end") (not cal)) do
+        (setq ce-rps (position (char cal 0) enemy-rps))
+        ;; We reuse numbers 1,2,3 to, for now, signify your strategy
+        (setq cy-rps (position (char cal 2) your-rps))
+
+        ;; Similarly to part-one.cl, if we write down the table of possible combinations
+        ;; (from left to right, columns are "Your strategy", "Enemy choice", "What your choice should be"):
+        ;; 1 1 | 3 = 1 + 2
+        ;; 1 2 | 1 = 1 + 0
+        ;; 1 3 | 2 = 1 + 1
+        ;; ----+----------
+        ;; 2 1 | 1 = 1 + 0
+        ;; 2 2 | 2 = 1 + 1
+        ;; 2 3 | 3 = 1 + 2
+        ;; ----+----------
+        ;; 3 1 | 2 = 1 + 1
+        ;; 3 2 | 3 = 1 + 2
+        ;; 3 3 | 1 = 1 + 0
+        ;; Your choice is a rotation of the numbers 1, 2 and 3, where if your strategy is 1 (lose)
+        ;; you rotate once, if your strategy is 2 (draw) you rotate zero times and if it is 3 (win)
+        ;; you rotate two times.
+        (setq cy-rps (+ (mod (+ cy-rps ce-rps) 3) 1))
+
+        ;; Refer to part-one.cl for explanation on math
+        (setq total-score (+ total-score (* 3 (mod (+ (- 4 ce-rps) cy-rps) 3)) cy-rps))
+
+        (setq cal (read-line *prog-input* NIL)))
+
+  (print total-score))
+
+(if (not (eq *prog-input* *standard-input*))
+  (close *prog-input*))
+