Merge pull request #1524 from ivanpenaloza/january22

adding algo

Author: ivanpenaloza

src/my_project/interviews/top_150_questions_round_22/ex_56_add_two_numbers.py

@@ -0,0 +1,42 @@
+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
+
+
+

src/my_project/interviews_typescript/top_150_questions_round_1/ListNode.ts

@@ -0,0 +1,8 @@
+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)
+    }
+}

src/my_project/interviews_typescript/top_150_questions_round_1/ex_55_linked_list_cycle.ts

@@ -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 {
     /**

src/my_project/interviews_typescript/top_150_questions_round_1/ex_56_add_two_numbers.ts

@@ -0,0 +1,28 @@
+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;
+}

tests/test_150_questions_round_22/test_56_add_two_numbers_round_22.py

@@ -0,0 +1,75 @@
+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)