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def load_data(file):
with open(file) as f:
data = f.read()
return [d for d in data.split("\n") if len(d) > 0]
def sign(x):
return 1 if abs(x) == x else -1
class Keypad:
def __init__(self):
keypad = self.build_keypad()
self.M = len(keypad)
self.N = len(keypad[0])
self.keypad = keypad
def build_keypad(self):
raise NotImplementedError()
def get_pos(self, key: str):
for i in range(self.M):
for j in range(self.N):
if self.keypad[i][j] == key:
return (i, j)
raise ValueError(f"Key {key} not found")
def get_distance(self, key_a: str, key_b: str):
pos_a = self.get_pos(key_a)
pos_b = self.get_pos(key_b)
dx = pos_b[0] - pos_a[0]
dy = pos_b[1] - pos_a[1]
return (dx, dy)
def __repr__(self):
return "\n".join([str(k) for k in self.keypad])
def pprint(self):
print("\n".join([str(k) for k in self.keypad]))
def find_sequence(self, key, next_key):
"""Finds the valid sequence between 2 key presses. Sequence returend is a string of button pushes."""
start_pos = self.get_pos(key)
if key == next_key:
return ""
distance = self.get_distance(key, next_key)
X = distance[0]
Y = distance[1]
# Strategy is to always try going >>>>, ^^^^^ until reaching, or other way around
# Keep track of the things you pass by, if you pass by an illegal move, then no good
seq_1 = [] # Actual button presses
pass_by_1 = [] # Keeps track of keys visited in sequence
i, j = start_pos
for dx in range(abs(X)):
i += 1*sign(X)
pass_by_1.append(self.keypad[i][j])
seq_1.append("v" if sign(X) == 1 else "^")
for dy in range(abs(Y)):
j += 1*sign(Y)
pass_by_1.append(self.keypad[i][j])
seq_1.append(">" if sign(Y) == 1 else "<")
# if not None in pass_by:
# return "".join(sequence)
seq_2 = []
pass_by_2 = []
i, j = start_pos
for dy in range(abs(Y)):
j += 1*sign(Y)
pass_by_2.append(self.keypad[i][j])
seq_2.append(">" if sign(Y) == 1 else "<")
for dx in range(abs(X)):
i += 1*sign(X)
pass_by_2.append(self.keypad[i][j])
seq_2.append("v" if sign(X) == 1 else "^")
if None in pass_by_1:
return "".join(seq_2)
elif None in pass_by_2:
return "".join(seq_1)
# We have a tie-break, so compute the cost of pressing the first key and tie-break based on that
cost = {
"^": 0,
">": 0,
"v": 1,
"<": 2,
}
cost_1 = cost[seq_1[0]]
cost_2 = cost[seq_2[0]]
# I swear i thought this should be <= but can't figure out why its >=
# seq = seq_1 if cost_1 <= cost_2 else seq_2
seq = seq_1 if cost_1 >= cost_2 else seq_2
# if cost_1 != cost_2:
# print(seq_1)
# print(seq_2)
# print(seq)
# print()
return "".join(seq)
def find_full_sequence(self, sequence: str):
# A robot always points at the A key first
start_key = "A"
full_sequence = []
key = start_key
for next_key in sequence:
full_sequence.append(self.find_sequence(key, next_key))
key = next_key
return "A".join(full_sequence) + "A" # Account for each button press needed and final button press
class NumericKeypad(Keypad):
def build_keypad(self):
return [
["7", "8", "9"],
["4", "5", "6"],
["1", "2", "3"],
[None, "0", "A"],
]
class DirectionalKeypad(Keypad):
def build_keypad(self):
return [
[None, "^", "A"],
["<", "v", ">"],
]
def complexity(code, sequence):
l = len(sequence)
n = int(code.split("A")[0])
# print(l, n)
return n*l
file = "input.txt"
# file = "test.txt"
data = load_data(file)
dir_keypad = DirectionalKeypad()
num_keypad = NumericKeypad()
total = 0
for code in data:
seq = num_keypad.find_full_sequence(code)
# print(code)
# print(seq)
for _ in range(2):
seq = dir_keypad.find_full_sequence(seq)
# print(seq)
c = complexity(code, seq)
total += c
# print(seq)
print(total)
## Part 2
# Simulating the whole process won't work, grows exponentially, must be more clever than that
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