Refactoring

src/Year_2015/P1.py

@@ -32,12 +32,12 @@
 # To what floor do the instructions take Santa?
 
 with open("files/P1.txt") as f:
-    directions = [line for line in f.read().strip().split()]
+    directions = f.read().strip()
 
 
 def part_1() -> None:
-    up = int(directions[0].count("("))
-    down = int(directions[0].count(")"))
+    up = directions.count("(")
+    down = directions.count(")")
     print(f"The floor is {up - down}")
 
 
@@ -58,14 +58,15 @@ def part_1() -> None:
 
 def part_2() -> None:
     floor = 0
-    for idx, char in enumerate(directions[0], start=1):
+    for idx, char in enumerate(directions, start=1):
         if char == "(":
             floor += 1
         elif char == ")":
             floor -= 1
         if floor == -1:
             print(f"The position is {idx}")
-            break
+            return
+    print("Basement was never reached!")
 
 
 if __name__ == "__main__":

src/Year_2015/P3.py

@@ -21,41 +21,29 @@
 #     ^v^v^v^v^v delivers a bunch of presents to some very lucky children at
 # only 2 houses.
 
-from typing import Tuple
-
 with open("files/P3.txt") as f:
-    moves = [line for line in f.read().strip().split()][0]
+    moves = [line for line in f.read().strip()]
 
 
-def move_up(pos: Tuple[int, int]) -> Tuple[int, int]:
-    return pos[0], pos[1] + 1
-
-
-def move_down(pos: Tuple[int, int]) -> Tuple[int, int]:
-    return pos[0], pos[1] - 1
-
-
-def move_left(pos: Tuple[int, int]) -> Tuple[int, int]:
-    return pos[0] - 1, pos[1]
-
-
-def move_right(pos: Tuple[int, int]) -> Tuple[int, int]:
-    return pos[0] + 1, pos[1]
+Position = tuple[int, int]
+DIRECTIONS: dict[str, Position] = {
+    "^": (0, 1),
+    "v": (0, -1),
+    "<": (-1, 0),
+    ">": (1, 0),
+}
 
 
 def part_1() -> None:
-    pos = [(0, 0)]
+    x, y = 0, 0
+    visited: set[Position] = {(x, y)}
     for move in moves:
-        if move == "^":
-            pos.append(move_up(pos[-1]))
-        elif move == "v":
-            pos.append(move_down(pos[-1]))
-        elif move == "<":
-            pos.append(move_left(pos[-1]))
-        elif move == ">":
-            pos.append(move_right(pos[-1]))
+        delta_x, delta_y = DIRECTIONS[move]
+        x += delta_x
+        y += delta_y
+        visited.add((x, y))
 
-    print(f"{len(set(pos))} houses receive at least one present")
+    print(f"{len(visited)} houses receive at least one present")
 
 
 # --- Part Two ---
@@ -81,33 +69,23 @@ def part_1() -> None:
 
 
 def part_2():
-    santa = [(0, 0)]
-    robo_santa = [(0, 0)]
-    for idx, move in enumerate(moves):
-        if move == "^":
-            if idx % 2 == 0:
-                santa.append(move_up(santa[-1]))
-            else:
-                robo_santa.append(move_up(robo_santa[-1]))
-        elif move == "v":
-            if idx % 2 == 0:
-                santa.append(move_down(santa[-1]))
-            else:
-                robo_santa.append(move_down(robo_santa[-1]))
-        elif move == "<":
-            if idx % 2 == 0:
-                santa.append(move_left(santa[-1]))
-            else:
-                robo_santa.append(move_left(robo_santa[-1]))
-        elif move == ">":
-            if idx % 2 == 0:
-                santa.append(move_right(santa[-1]))
-            else:
-                robo_santa.append(move_right(robo_santa[-1]))
+    x_santa, y_santa = 0, 0
+    x_robo, y_robo = 0, 0
+    visited: set[Position] = {(0, 0)}
 
-    print(
-        f"{len(set(santa + robo_santa))} houses receive at least one present"
-    )
+    for idx, move in enumerate(moves):
+        delta_x, delta_y = DIRECTIONS[move]
+        # santa's turn
+        if idx % 2:
+            x_santa += delta_x
+            y_santa += delta_y
+            visited.add((x_santa, y_santa))
+        else:
+            x_robo += delta_x
+            y_robo += delta_y
+            visited.add((x_robo, y_robo))
+
+    print(f"{len(visited)} houses receive at least one present")
 
 
 if __name__ == "__main__":

src/Year_2015/P4.py

@@ -18,21 +18,30 @@
 # an MD5 hash starting with five zeroes is 1048970; that is, the MD5 hash of
 # pqrstuv1048970 looks like 000006136ef....
 
-# Your puzzle input is yzbqklnj.
 
 from hashlib import md5
+from itertools import count
 
-_input = "yzbqklnj"
+with open("files/P4.txt") as f:
+    secret_key = f.read().strip()
+
+key_bytes = secret_key.encode()
 
 
 def part_1() -> None:
-    end = "9" * len(_input)
-    for num in range(int(end)):
-        testing = _input + str(num)
-        result = md5(testing.encode()).hexdigest()
-        if result.startswith("0" * 5):
-            print(f"The lowest positive number is {num}")
-            break
+    padding = 5
+    prefix = "0" * padding
+    base_hash = md5(key_bytes)
+
+    for num in count(1):
+        digest_ctx = base_hash.copy()
+        digest_ctx.update(str(num).encode())
+        digest = digest_ctx.hexdigest()
+        if digest.startswith(prefix):
+            print(f"The lowest positive number starting with {padding} zeroes is {num}")
+            return
+
+    raise RuntimeError("No valid number found")
 
 
 # --- Part Two ---
@@ -41,13 +50,19 @@ def part_1() -> None:
 
 
 def part_2() -> None:
-    end = "9" * len(_input)
-    for num in range(int(end)):
-        testing = _input + str(num)
-        result = md5(testing.encode()).hexdigest()
-        if result.startswith("0" * 6):
-            print(f"The lowest positive number is {num}")
-            break
+    padding = 6
+    prefix = "0" * padding
+    base_hash = md5(key_bytes)
+
+    for num in count(1):
+        digest_ctx = base_hash.copy()
+        digest_ctx.update(str(num).encode())
+        digest = digest_ctx.hexdigest()
+        if digest.startswith(prefix):
+            print(f"The lowest positive number starting with {padding} zeroes is {num}")
+            return
+
+    raise RuntimeError("No valid number found")
 
 
 if __name__ == "__main__":

src/Year_2015/P5.py

@@ -25,44 +25,32 @@
 
 # How many strings are nice?
 
-from collections import Counter
-
 with open("files/P5.txt") as f:
     strings = [line for line in f.read().strip().split()]
 
+VOWELS = set("aeiou")
+FORBIDDEN = ("ab", "cd", "pq", "xy")
+
 
 def has_enough_vowels(s: str) -> bool:
-    num_vowels = sum(s.lower().count(v) for v in "aeiou")
-    if num_vowels >= 3:
-        return True
-    return False
+    return sum(char in VOWELS for char in s) >= 3
 
 
 def has_double_letter(s: str) -> bool:
-    double_letters = sum(1 for i, j in zip(s, s[1:]) if i == j)
-    if double_letters >= 1:
-        return True
-    return False
+    return any(left == right for left, right in zip(s, s[1:]))
 
 
 def has_substring(s: str) -> bool:
-    substrings = ["ab", "cd", "pq", "xy"]
-    for substring in substrings:
-        if substring in s:
-            return True
-    return False
+    return any(substring in s for substring in FORBIDDEN)
 
 
 def part_1() -> None:
-    nice = 0
-    for string in strings:
-        if (
+    nice = sum(
         has_enough_vowels(string)
         and has_double_letter(string)
         and not has_substring(string)
-        ):
-            nice += 1
-
+        for string in strings
+    )
     print(f"There are {nice} nice strings")
 
 
@@ -103,18 +91,11 @@ def has_pairs(s: str) -> bool:
 
 
 def has_letter_between(s: str) -> bool:
-    _my_str = zip(s, s[1:], s[2:])
-    for triple in _my_str:
-        if triple[0] == triple[-1]:
-            return True
-    return False
+    return any(a == c for a, _, c in zip(s, s[1:], s[2:]))
 
 
 def part_2() -> None:
-    nice = 0
-    for string in strings:
-        if has_pairs(string) and has_letter_between(string):
-            nice += 1
+    nice = sum(has_pairs(string) and has_letter_between(string) for string in strings)
     print(f"There are {nice} nicer strings")