adding algo

src/my_project/interviews/top_150_questions_round_22/ex_91_minimum_genetic_mutation.py

@@ -0,0 +1,52 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+from collections import deque, defaultdict
+
+class Solution:
+    def minMutation(self, startGene: str, endGene: str, bank: List[str]) -> int:
+        """
+        Find minimum number of mutations from startGene to endGene.
+        Uses BFS to find shortest path. Each mutation changes one character,
+        and the resulting gene must be in the bank.
+
+        Time Complexity: O(N * L * 4) where N is bank size, L is gene length (8)
+        Space Complexity: O(N) for visited set and queue
+        """
+        # If endGene is not in bank, it's impossible
+        if endGene not in bank:
+            return -1
+
+        # Convert bank to set for O(1) lookup
+        bank_set = set(bank)
+
+        # BFS queue: (current_gene, mutation_count)
+        queue = deque([(startGene, 0)])
+        visited = {startGene}
+
+        # Possible gene characters
+        genes = ['A', 'C', 'G', 'T']
+
+        while queue:
+            current_gene, mutations = queue.popleft()
+
+            # If we reached the end gene, return the mutation count
+            if current_gene == endGene:
+                return mutations
+
+            # Try all possible single character mutations
+            for i in range(len(current_gene)):
+                for gene_char in genes:
+                    # Skip if same character
+                    if gene_char == current_gene[i]:
+                        continue
+
+                    # Create mutated gene
+                    mutated = current_gene[:i] + gene_char + current_gene[i+1:]
+
+                    # If mutation is valid and not visited
+                    if mutated in bank_set and mutated not in visited:
+                        visited.add(mutated)
+                        queue.append((mutated, mutations + 1))
+
+        # No path found
+        return -1

src/my_project/interviews_typescript/top_150_questions_round_1/ex_90_snakes_and_ladders.ts

@@ -60,31 +60,4 @@ function snakesAndLadders(board: number[][]): number {
 
     // If we can't reach the target
     return -1;
-}
-
-// Test cases
-console.log("Example 1:");
-const board1 = [
-    [-1,-1,-1,-1,-1,-1],
-    [-1,-1,-1,-1,-1,-1],
-    [-1,-1,-1,-1,-1,-1],
-    [-1,35,-1,-1,13,-1],
-    [-1,-1,-1,-1,-1,-1],
-    [-1,15,-1,-1,-1,-1]
-];
-console.log(`Input: board = ${JSON.stringify(board1)}`);
-console.log(`Output: ${snakesAndLadders(board1)}`); // Expected: 4
-console.log(`Explanation: In the beginning, you start at square 1 (at row 5, column 0).
-You decide to move to square 2 and must take the ladder to square 15.
-You then decide to move to square 17 and must take the snake to square 13.
-You then decide to move to square 14 and must take the ladder to square 35.
-You then decide to move to square 36, ending the game.
-This is the lowest possible number of moves to reach the last square, so return 4.`);
-
-console.log("\nExample 2:");
-const board2 = [[-1,-1],[-1,3]];
-console.log(`Input: board = ${JSON.stringify(board2)}`);
-console.log(`Output: ${snakesAndLadders(board2)}`); // Expected: 1
-
-export { snakesAndLadders };
-
+}