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Merged
ivanpenaloza merged 1 commit into from
Jan 22, 2026
Merged

adding algo #1524

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42 changes: 42 additions & 0 deletions src/my_project/interviews/top_150_questions_round_22/ex_56_add_two_numbers.py
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Original file line number Diff line number Diff line change
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from typing import List, Union, Collection, Mapping, Optional
from abc import ABC, abstractmethod

# Definition for singly-linked list.
class ListNode:
def __init__(self, x):
self.val = x
self.next = None

class Solution(object):
def addTwoNumbers(self, l1, l2):
"""
:type l1: ListNode
:type l2: ListNode
:rtype: ListNode
"""
dummy = ListNode(0)
current = dummy
carry = 0

while l1 or l2 or carry:
# Get values from current nodes (0 if node is None)
val1 = l1.val if l1 else 0
val2 = l2.val if l2 else 0

# Calculate sum and carry
total = val1 + val2 + carry
carry = total // 10
digit = total % 10

# Create new node with the digit
current.next = ListNode(digit)
current = current.next

# Move to next nodes if available
l1 = l1.next if l1 else None
l2 = l2.next if l2 else None

return dummy.next



8 changes: 8 additions & 0 deletions src/my_project/interviews_typescript/top_150_questions_round_1/ListNode.ts
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export class ListNode {
val: number
next: ListNode | null
constructor(val?: number, next?: ListNode | null) {
this.val = (val===undefined ? 0 : val)
this.next = (next===undefined ? null : next)
}
}
10 changes: 1 addition & 9 deletions src/my_project/interviews_typescript/top_150_questions_round_1/ex_55_linked_list_cycle.ts
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@@ -1,12 +1,4 @@
class ListNode {
val: number
next: ListNode | null
constructor(val?: number, next?: ListNode | null) {
this.val = (val===undefined ? 0 : val)
this.next = (next===undefined ? null : next)
}
}

import { ListNode } from './ListNode';

function hasCycle(head: ListNode | null): boolean {
/**
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28 changes: 28 additions & 0 deletions src/my_project/interviews_typescript/top_150_questions_round_1/ex_56_add_two_numbers.ts
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import { ListNode } from './ListNode';

function addTwoNumbers(l1: ListNode | null, l2: ListNode | null): ListNode | null {
const dummy = new ListNode(0);
let current = dummy;
let carry = 0;

while (l1 || l2 || carry) {
// Get values from current nodes (0 if node is null)
const val1 = l1 ? l1.val : 0;
const val2 = l2 ? l2.val : 0;

// Calculate sum and carry
const total = val1 + val2 + carry;
carry = Math.floor(total / 10);
const digit = total % 10;

// Create new node with the digit
current.next = new ListNode(digit);
current = current.next;

// Move to next nodes if available
l1 = l1 ? l1.next : null;
l2 = l2 ? l2.next : null;
}

return dummy.next;
}
75 changes: 75 additions & 0 deletions tests/test_150_questions_round_22/test_56_add_two_numbers_round_22.py
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import unittest
from src.my_project.interviews.top_150_questions_round_22\
.ex_56_add_two_numbers import Solution, ListNode


class AddTwoLinkedListsTestCase(unittest.TestCase):

def create_linked_list(self, values):
"""
Helper function to create a linked list from a list of values.

:param values: List of node values
:return: Head of the linked list
"""
if not values:
return None

head = ListNode(values[0])
current = head

for val in values[1:]:
current.next = ListNode(val)
current = current.next

return head

def linked_list_to_list(self, head):
"""
Helper function to convert linked list to Python list.

:param head: Head of the linked list
:return: List of values
"""
result = []
current = head

while current:
result.append(current.val)
current = current.next

return result

def test_first_pattern(self):
# Input: l1 = [2,4,3], l2 = [5,6,4]
# Output: [7,0,8]
# Explanation: 342 + 465 = 807
solution = Solution()
l1 = self.create_linked_list([2, 4, 3])
l2 = self.create_linked_list([5, 6, 4])
output = solution.addTwoNumbers(l1, l2)
result = self.linked_list_to_list(output)
target = [7, 0, 8]
self.assertEqual(result, target)

def test_second_pattern(self):
# Input: l1 = [0], l2 = [0]
# Output: [0]
solution = Solution()
l1 = self.create_linked_list([0])
l2 = self.create_linked_list([0])
output = solution.addTwoNumbers(l1, l2)
result = self.linked_list_to_list(output)
target = [0]
self.assertEqual(result, target)

def test_third_pattern(self):
# Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]
# Output: [8,9,9,9,0,0,0,1]
solution = Solution()
l1 = self.create_linked_list([9, 9, 9, 9, 9, 9, 9])
l2 = self.create_linked_list([9, 9, 9, 9])
output = solution.addTwoNumbers(l1, l2)
result = self.linked_list_to_list(output)
target = [8, 9, 9, 9, 0, 0, 0, 1]
self.assertEqual(result, target)