cache attempt, not work

examples/aoc2024/day21/part2.jou

@@ -1,4 +1,5 @@
 import "stdlib/io.jou"
+import "stdlib/mem.jou"
 import "stdlib/ascii.jou"
 import "stdlib/math.jou"
 import "stdlib/str.jou"
@@ -31,14 +32,27 @@ class KeyPad:
         assert False
 
 
+# cache[nkeypads][key_to_press][old_x][old_y] = return value if not random, 0 if uninitialized
+global cache: long[5][5][128][30]
+
+
 # Recursive function. Before we recurse, parameters are:
 #   first keypad = the numeric keypad attached to door (the only numeric)
 #   last keypad = the keypad that a human is typing into
 #
 # Return value = how many times total the keys on last keypad were pressed.
-def press_key(keypads: KeyPad*, nkeypads: int, key_to_press: byte) -> long:
-#    printf("Press '%c'\n", key_to_press)
-#    fflush(stdout)
+def press_key(
+    keypads: KeyPad*,
+    nkeypads: int,
+    key_to_press: byte,
+    random_flag: bool*  # set to true if randomness is involved, otherwise not used
+) -> long:
+    if nkeypads >= 20:
+        k = 28-nkeypads
+        while k --> 0:
+            printf("  ")
+        printf("(%d) press '%c'\n", nkeypads, key_to_press)
+        fflush(stdout)
 
     if nkeypads == 1:
         # Human is typing here, let's simply count the key presses.
@@ -56,6 +70,10 @@ def press_key(keypads: KeyPad*, nkeypads: int, key_to_press: byte) -> long:
     dx = new_x - old_x
     dy = new_y - old_y
 
+    cacheptr = &cache[nkeypads][key_to_press][old_x][old_y]
+    if *cacheptr != 0:
+        return *cacheptr
+
     if dx < 0:
         dx_key = '<'
         dx_step = -1
@@ -74,6 +92,8 @@ def press_key(keypads: KeyPad*, nkeypads: int, key_to_press: byte) -> long:
     v_first_blocked = (keypads[0].get(old_x, new_y) == ' ')
     assert not (h_first_blocked and v_first_blocked)
 
+    this_call_is_random = False
+
     if dx == 0 or dy == 0:
         # order doesn't matter
         assert not h_first_blocked
@@ -88,40 +108,48 @@ def press_key(keypads: KeyPad*, nkeypads: int, key_to_press: byte) -> long:
         # Let's choose 50% randomly because I can't think of a good way
         # to figure out what's best.
         horizontal_first = (rand() % 100 >= 50)
+        this_call_is_random = True
 
     result = 0L
 
     if horizontal_first:
         n = abs(dx)
         while n --> 0:
-            result += press_key(&keypads[1], nkeypads - 1, dx_key)
+            result += press_key(&keypads[1], nkeypads - 1, dx_key, &this_call_is_random)
             keypads[1].aimed_at_x += dx_step
 
         n = abs(dy)
         while n --> 0:
-            result += press_key(&keypads[1], nkeypads - 1, dy_key)
+            result += press_key(&keypads[1], nkeypads - 1, dy_key, &this_call_is_random)
             keypads[1].aimed_at_y += dy_step
     else:
         n = abs(dy)
         while n --> 0:
-            result += press_key(&keypads[1], nkeypads - 1, dy_key)
+            result += press_key(&keypads[1], nkeypads - 1, dy_key, &this_call_is_random)
             keypads[1].aimed_at_y += dy_step
 
         n = abs(dx)
         while n --> 0:
-            result += press_key(&keypads[1], nkeypads - 1, dx_key)
+            result += press_key(&keypads[1], nkeypads - 1, dx_key, &this_call_is_random)
             keypads[1].aimed_at_x += dx_step
 
     assert keypads[1].aimed_at_x == new_x
     assert keypads[1].aimed_at_y == new_y
     assert keypads[0].get(new_x, new_y) == key_to_press
 
-    result += press_key(&keypads[1], nkeypads - 1, 'A')
+    result += press_key(&keypads[1], nkeypads - 1, 'A', &this_call_is_random)
+
+    if this_call_is_random:
+        *random_flag = True
+#    else:
+#        *cacheptr = result
+
     return result
 
 
 def main() -> int:
     srand(123)
+    memset(&cache, 0, sizeof(cache))
 
     numeric_keypad = KeyPad{
         rows = [
@@ -143,6 +171,29 @@ def main() -> int:
 
     initial_keypads = [
         numeric_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
+#        arrow_keypad,
         arrow_keypad,
         arrow_keypad,
         arrow_keypad,
@@ -172,7 +223,8 @@ def main() -> int:
 
             counter = 0L
             for i = 0; line[i] != '\0'; i++:
-                counter += press_key(keypads, sizeof(keypads)/sizeof(keypads[0]) as int, line[i])
+                dummy: bool
+                counter += press_key(keypads, sizeof(keypads)/sizeof(keypads[0]) as int, line[i], &dummy)
 
             if best == -1 or counter < best:
                 printf("  (k=%lld) new best: %lld\n", k, counter)