aoc/2021/18/solution.py

#!/usr/bin/env python3
import sys
import re

class Node:
    def __init__(self, left = None, right = None, value = None):
        self.left = left
        self.right = right
        self.value = value
        self.parent = None
    
    def __str__(self):
        return str(self.value) if self.value != None else f"[{str(self.left)}, {str(self.right)}]"
       
    def insert(self, node):
        if not self.left:
            self.left = node
            self.left.parent = self
        else:
            self.right = node
            self.right.parent = self
    
    def is_leaf(self):
        return self.left == None and self.right == None
    
    def is_left(self):
        return self.parent and self.parent.left == self

    def is_right(self):
        return self.parent and self.parent.right == self

def parse_snailfishes(str):
    stack = [Node()]
    for c in str:
        if c == '[':
            stack.append(Node())
            continue
        if c == ']':
            node = stack.pop()
            stack[-1].insert(node)
            continue
        if c == ',':
            continue
        # if none apply insert as number
        stack[-1].insert(Node(value=int(c)))
    return stack.pop()

def explode(node, value, left):
    #print(f'@ {node}')
    #print(f'@ {node.parent}')
    current = node
    while current.parent != None and ((current.is_left() and current.parent.right.value != None) or (current.is_right() and current.parent.left.value != None)):
        current = current.parent
    current = current.left if left else current.right
    while current.right if left else current.left != None:
        current = current.right if left else current.left
    #print(f'reached node {current} ({"left" if left else "right"})')
    if current.value != None:
        current.value += value
    return True

def reduce_snailfishes(node, level = 1):
    current = node
    reduced = False
    #print(f'level {level}')
    if level > 3 and current.left.is_leaf() and current.right.is_leaf():
        print(f'exploding {current} distributing {current.left} and {current.right}')
        # search left spot
        reduced = reduced or explode(current, current.left.value, True)
        reduced = reduced or explode(current, current.right.value, False)
        # search right spot
        if current.is_left():
            current.parent.left = Node(value=0)
        if current.is_right():
            current.parent.right = Node(value=0)
        #explode_right(current, current.right)
        return reduced
    if not current.left.is_leaf():
        reduced = reduced or reduce_snailfishes(current.left, level + 1)
    if not current.right.is_leaf():
        reduced = reduced or reduce_snailfishes(current.right, level + 1)
    return reduced

def add_snailfishes(node1, node2):
    print(f'adding {node1} and {node2}')
    node = Node(node1, node2)
    node.left.parent = node
    node.right.parent = node
    print(f'into {node}')
    while reduce_snailfishes(node):
        print(f'reducing again {node}')
    print(f'reduced to {node}')

numbers = []
for line in sys.stdin:
    print(f"new line:  ", line.rstrip('\n'))
    numbers.append(parse_snailfishes(line.rstrip('\n')[1:-1]))

print([str(n) for n in numbers])
node1 = numbers[0]
for i in range(1, len(numbers) * 0):
    node2 = numbers[i]
    add_snailfishes(node1, node2)
    node1 = node2

add_snailfishes(numbers[3], numbers[4])