Merge pull request #1593 from ivanpenaloza/march31

adding algo

Author: ivanpenaloza

src/my_project/interviews/amazon_high_frequency_23/common_algos/two_sum_round_2.py

@@ -0,0 +1,21 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+
+        answer = dict()
+
+        for k, v in enumerate(nums):
+
+            if v in answer:
+                return [answer[v], k]
+            else:
+                answer[target - v] = k
+            
+        return []
+
+
+
+        
+

src/my_project/interviews/amazon_high_frequency_23/common_algos/valid_palindrome_round_2.py

@@ -0,0 +1,22 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+import re
+
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+
+        # To lowercase
+        s = s.lower()
+
+        # Remove non-alphanumeric characters
+        s = re.sub(pattern=r'[^a-zA-Z0-9]', repl='', string=s)
+
+        # Determine if s is palindrome or not
+        len_s = len(s)
+
+        for i in range(len_s//2):
+
+            if s[i] != s[len_s - 1 - i]:
+                return False
+            
+        return True 

src/my_project/interviews/top_150_questions_round_22/ex_116_kth_largest_element_in_array.py

@@ -0,0 +1,37 @@
+import random
+from typing import List
+
+
+class Solution:
+    def findKthLargest(self, nums: List[int], k: int) -> int:
+        target = len(nums) - k
+
+        def quickselect(left: int, right: int) -> int:
+            pivot_index = random.randint(left, right)
+            pivot = nums[pivot_index]
+
+            # 3-way partition (Dutch National Flag)
+            low = left
+            mid = left
+            high = right
+
+            while mid <= high:
+                if nums[mid] < pivot:
+                    nums[low], nums[mid] = nums[mid], nums[low]
+                    low += 1
+                    mid += 1
+                elif nums[mid] > pivot:
+                    nums[mid], nums[high] = nums[high], nums[mid]
+                    high -= 1
+                else:
+                    mid += 1
+
+            # All elements equal to pivot are in [low, high]
+            if target < low:
+                return quickselect(left, low - 1)
+            elif target > high:
+                return quickselect(high + 1, right)
+            else:
+                return nums[target]
+
+        return quickselect(0, len(nums) - 1)

src/my_project/interviews_typescript/top_150_questions_round_1/ex_116_kth_largest_element_in_array.ts

@@ -0,0 +1,37 @@
+function findKthLargest(nums: number[], k: number): number {
+    const target = nums.length - k;
+
+    function quickselect(left: number, right: number): number {
+        const pivotIndex = left + Math.floor(Math.random() * (right - left + 1));
+        const pivot = nums[pivotIndex];
+
+        // 3-way partition (Dutch National Flag)
+        let low = left;
+        let mid = left;
+        let high = right;
+
+        while (mid <= high) {
+            if (nums[mid] < pivot) {
+                [nums[low], nums[mid]] = [nums[mid], nums[low]];
+                low++;
+                mid++;
+            } else if (nums[mid] > pivot) {
+                [nums[mid], nums[high]] = [nums[high], nums[mid]];
+                high--;
+            } else {
+                mid++;
+            }
+        }
+
+        // All elements equal to pivot are in [low, high]
+        if (target < low) {
+            return quickselect(left, low - 1);
+        } else if (target > high) {
+            return quickselect(high + 1, right);
+        } else {
+            return nums[target];
+        }
+    }
+
+    return quickselect(0, nums.length - 1);
+};

tests/test_150_questions_round_22/test_116_kth_largest_element_in_array_round_22.py

@@ -0,0 +1,72 @@
+import unittest
+from typing import List
+from src.my_project.interviews.top_150_questions_round_22\
+    .ex_116_kth_largest_element_in_array import Solution
+
+
+class KthLargestElementTestCase(unittest.TestCase):
+    def setUp(self):
+        self.solution = Solution()
+
+    def test_example_1(self):
+        """Test: nums = [3,2,1,5,6,4], k = 2, expected = 5"""
+        nums = [3, 2, 1, 5, 6, 4]
+        k = 2
+        result = self.solution.findKthLargest(nums, k)
+        self.assertEqual(result, 5)
+
+    def test_example_2(self):
+        """Test: nums = [3,2,3,1,2,4,5,5,6], k = 4, expected = 4"""
+        nums = [3, 2, 3, 1, 2, 4, 5, 5, 6]
+        k = 4
+        result = self.solution.findKthLargest(nums, k)
+        self.assertEqual(result, 4)
+
+    def test_single_element(self):
+        """Test: nums = [1], k = 1, expected = 1"""
+        nums = [1]
+        k = 1
+        result = self.solution.findKthLargest(nums, k)
+        self.assertEqual(result, 1)
+
+    def test_all_same_elements(self):
+        """Test: nums = [3,3,3,3], k = 2, expected = 3"""
+        nums = [3, 3, 3, 3]
+        k = 2
+        result = self.solution.findKthLargest(nums, k)
+        self.assertEqual(result, 3)
+
+    def test_k_equals_length(self):
+        """Test: nums = [7,6,5,4,3,2,1], k = 7, expected = 1"""
+        nums = [7, 6, 5, 4, 3, 2, 1]
+        k = 7
+        result = self.solution.findKthLargest(nums, k)
+        self.assertEqual(result, 1)
+
+    def test_k_equals_1(self):
+        """Test: nums = [2,1,4,3], k = 1, expected = 4"""
+        nums = [2, 1, 4, 3]
+        k = 1
+        result = self.solution.findKthLargest(nums, k)
+        self.assertEqual(result, 4)
+
+    def test_negative_numbers(self):
+        """Test: nums = [-1,-2,-3,-4], k = 2, expected = -2"""
+        nums = [-1, -2, -3, -4]
+        k = 2
+        result = self.solution.findKthLargest(nums, k)
+        self.assertEqual(result, -2)
+
+    def test_duplicates_with_target(self):
+        """Test: nums = [1,2,2,3,3,4], k = 3, expected = 3"""
+        nums = [1, 2, 2, 3, 3, 4]
+        k = 3
+        result = self.solution.findKthLargest(nums, k)
+        self.assertEqual(result, 3)
+
+    def test_two_elements(self):
+        """Test: nums = [2,1], k = 1, expected = 2"""
+        nums = [2, 1]
+        k = 1
+        result = self.solution.findKthLargest(nums, k)
+        self.assertEqual(result, 2)