Advent of code 2022 - Day 20 solution

20.py

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None
        self.prev = None

    def __str__(self):
        return f'[{str(self.value)}]'
    
    def __repr__(self):
        return self.__str__()

class LinkedList:
    def __init__(self):
        self.head = Node(None)
        self.tail = Node(None)
        self.head.next = self.tail
        self.tail.prev = self.head
        self.size = 0
    
    def add(self, value):
        item = Node(value)
        item.prev = self.tail.prev
        item.next = self.tail
        self.tail.prev.next = item
        self.tail.prev = item
        self.size += 1
        return item
    
    def move(self, node, steps):
        # print("Move", node, steps)
        if steps == 0:
            return
        if steps > (self.size-1):
            steps = steps % (self.size-1)
        
        if steps < 0:
            stepsp = abs(steps)
            if stepsp > (self.size-1):
                stepsp = stepsp % (self.size-1)
            steps = self.size-1-stepsp
        
        node.prev.next = node.next
        node.next.prev = node.prev
        curr = node
        for _ in range(steps):
            curr = curr.next
            if curr == self.tail:
                curr = self.head.next
        
        node.next = curr.next
        node.prev = curr
        curr.next = node
        node.next.prev = node

    def result(self):
        curr = self.head.next
        while curr.value != 0:
            curr = curr.next
        ret = 0
        pos = 0 
        while pos <= 3000:
            curr = curr.next
            pos += 1
            if curr == self.tail:
                curr = self.head.next
            
            if pos == 1000 or pos == 2000 or pos == 3000:
                ret += curr.value
        return ret


    
    def __str__(self):
        curr = self.head
        ret = ''
        while curr != self.tail:
            if curr == self.head:
                curr = curr.next
                continue
            ret += f'{str(curr)} '
            curr = curr.next
        return ret
    
    def __repr__(self):
        return self.__str__()

def main(lines):
    lst = LinkedList()
    moves = []
    for line in lines:
        line = line.strip()
        moves.append(lst.add(int(line)))
    
    # print(lst)
    for m in moves:
        lst.move(m, m.value)
    # print(lst)
    print(lst.result())

def main2(lines):
    lst = LinkedList()
    moves = []
    dk = 811589153
    for line in lines:
        line = line.strip()
        moves.append(lst.add(int(line) * dk))
    
    # print(lst)
    for _ in range(10):
        for m in moves:
            lst.move(m, m.value)
    # print(lst)
    print(lst.result())


if __name__ == '__main__':
    with open('20.input') as f:
        lines = f.readlines()
    print("PART-1")
    main(lines)
    print("PART-2")
    main2(lines)