adding algo

src/my_project/interviews/amazon_high_frequency_23/common_algos/two_sum_round_6.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_6.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_95_word_search_ii.py

@@ -0,0 +1,62 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+from collections import deque, defaultdict
+
+class TrieNode:
+    def __init__(self):
+        self.children = {}
+        self.word = None  # Store the complete word at the end node
+
+class Solution:
+    def findWords(self, board: List[List[str]], words: List[str]) -> List[str]:
+        # Build Trie from words
+        root = TrieNode()
+        for word in words:
+            node = root
+            for char in word:
+                if char not in node.children:
+                    node.children[char] = TrieNode()
+                node = node.children[char]
+            node.word = word
+
+        m, n = len(board), len(board[0])
+        result = []
+
+        def dfs(i, j, node):
+            # Get current character
+            char = board[i][j]
+
+            # Check if character exists in Trie
+            if char not in node.children:
+                return
+
+            next_node = node.children[char]
+
+            # If we found a word, add it to result
+            if next_node.word:
+                result.append(next_node.word)
+                next_node.word = None  # Avoid duplicate results
+
+            # Mark cell as visited
+            board[i][j] = '#'
+
+            # Explore all 4 directions
+            for di, dj in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
+                ni, nj = i + di, j + dj
+                if 0 <= ni < m and 0 <= nj < n and board[ni][nj] != '#':
+                    dfs(ni, nj, next_node)
+
+            # Restore cell
+            board[i][j] = char
+
+            # Optimization: remove leaf nodes to prune the Trie
+            if not next_node.children:
+                del node.children[char]
+
+        # Start DFS from each cell
+        for i in range(m):
+            for j in range(n):
+                dfs(i, j, root)
+
+        return result
+

src/my_project/interviews_typescript/top_150_questions_round_1/ex_95_word_search_ii.ts

@@ -0,0 +1,78 @@
+class TrieNode {
+    children: Map<string, TrieNode>;
+    word: string | null;
+
+    constructor() {
+        this.children = new Map();
+        this.word = null; // Store the complete word at the end node
+    }
+}
+
+function findWords(board: string[][], words: string[]): string[] {
+    // Build Trie from words
+    const root = new TrieNode();
+    for (const word of words) {
+        let node = root;
+        for (const char of word) {
+            if (!node.children.has(char)) {
+                node.children.set(char, new TrieNode());
+            }
+            node = node.children.get(char)!;
+        }
+        node.word = word;
+    }
+
+    const m = board.length;
+    const n = board[0].length;
+    const result: string[] = [];
+
+    function dfs(i: number, j: number, node: TrieNode): void {
+        // Get current character
+        const char = board[i][j];
+
+        // Check if character exists in Trie
+        if (!node.children.has(char)) {
+            return;
+        }
+
+        const nextNode = node.children.get(char)!;
+
+        // If we found a word, add it to result
+        if (nextNode.word !== null) {
+            result.push(nextNode.word);
+            nextNode.word = null; // Avoid duplicate results
+        }
+
+        // Mark cell as visited
+        board[i][j] = '#';
+
+        // Explore all 4 directions
+        const directions = [[0, 1], [1, 0], [0, -1], [-1, 0]];
+        for (const [di, dj] of directions) {
+            const ni = i + di;
+            const nj = j + dj;
+            if (ni >= 0 && ni < m && nj >= 0 && nj < n && board[ni][nj] !== '#') {
+                dfs(ni, nj, nextNode);
+            }
+        }
+
+        // Restore cell
+        board[i][j] = char;
+
+        // Optimization: remove leaf nodes to prune the Trie
+        if (nextNode.children.size === 0) {
+            node.children.delete(char);
+        }
+    }
+
+    // Start DFS from each cell
+    for (let i = 0; i < m; i++) {
+        for (let j = 0; j < n; j++) {
+            dfs(i, j, root);
+        }
+    }
+
+    return result;
+}
+
+

tests/test_150_questions_round_22/test_95_word_search_ii_round.py

@@ -0,0 +1,55 @@
+import unittest
+from typing import Optional, List
+from src.my_project.interviews.top_150_questions_round_22\
+.ex_95_word_search_ii import Solution
+
+
+class WordSearchIITestCase(unittest.TestCase):
+
+    def test_example_1(self):
+        """
+        Input: board = [["o","a","a","n"],["e","t","a","e"],["i","h","k","r"],["i","f","l","v"]], 
+               words = ["oath","pea","eat","rain"]
+        Output: ["eat","oath"]
+        """
+        solution = Solution()
+        board = [
+            ["o", "a", "a", "n"],
+            ["e", "t", "a", "e"],
+            ["i", "h", "k", "r"],
+            ["i", "f", "l", "v"]
+        ]
+        words = ["oath", "pea", "eat", "rain"]
+        result = solution.findWords(board, words)
+        self.assertEqual(sorted(result), sorted(["eat", "oath"]))
+
+    def test_example_2(self):
+        """
+        Input: board = [["a","b"],["c","d"]], words = ["abcb"]
+        Output: []
+        """
+        solution = Solution()
+        board = [["a", "b"], ["c", "d"]]
+        words = ["abcb"]
+        result = solution.findWords(board, words)
+        self.assertEqual(result, [])
+
+    def test_single_cell(self):
+        """
+        Test with single cell board
+        """
+        solution = Solution()
+        board = [["a"]]
+        words = ["a", "b"]
+        result = solution.findWords(board, words)
+        self.assertEqual(result, ["a"])
+
+    def test_no_words_found(self):
+        """
+        Test when no words are found
+        """
+        solution = Solution()
+        board = [["a", "b"], ["c", "d"]]
+        words = ["xyz", "pqr"]
+        result = solution.findWords(board, words)
+        self.assertEqual(result, [])