Leetcode 1774 Solution

This article provides solution to leetcode question 1774 (add-two-polynomials-represented-as-linked-lists)
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https://leetcode.com/problems/add-two-polynomials-represented-as-linked-lists

Solution

# Definition for polynomial singly-linked list.
# class PolyNode:
#     def __init__(self, x=0, y=0, next=None):
#         self.coefficient = x
#         self.power = y
#         self.next = next

class Solution:
    def addPoly(self, poly1: 'PolyNode', poly2: 'PolyNode') -> 'PolyNode':
        dummy_head = PolyNode()

        prev_node = dummy_head
        node1 = poly1
        node2 = poly2

        while node1 or node2:
            power1 = node1.power if node1 else -1
            power2 = node2.power if node2 else -1

            v = 0
            power = 0
            if power1 == power2:
                v = node1.coefficient + node2.coefficient
                power = power1
                node1 = node1.next
                node2 = node2.next
            elif power1 > power2:
                v = node1.coefficient
                power = power1
                node1 = node1.next
            elif power1 < power2:
                v = node2.coefficient
                power = power2
                node2 = node2.next

            if v != 0:
                prev_node.next = PolyNode(v, power)
                prev_node = prev_node.next

        return dummy_head.next