adding 3 aws algos

Author: ivanpenaloza

src/my_project/interviews/amazon_high_frequency_23/round_2/lowest_common_ancestor.py

@@ -0,0 +1,25 @@
+from typing import List 
+
+class TreeNode:
+    def __init__(self, x):
+        self.val = x
+        self.left = None
+        self.right = None
+
+class Solution:
+    def lowestCommonAncestor(self, root: TreeNode, nodes: List[TreeNode]) -> 'TreeNode':
+        node_set = set(nodes)
+
+        def dfs(node: TreeNode):
+            if not node or node in node_set:
+                return node 
+            
+            left = dfs(node.left)
+            right = dfs(node.right)
+
+            if left and right: 
+                return node 
+            
+            return left if left else right 
+        
+        return dfs(root)

src/my_project/interviews/amazon_high_frequency_23/round_2/optimal_partition_string.py

@@ -0,0 +1,15 @@
+class Solution:
+    def partitionString(self, s: str) -> int:
+
+        last_pos = [0] * 26
+        partitions = 0
+        last_end = 0
+
+        for i in range(len(s)):
+            if last_pos[ord(s[i]) - ord('a')] >= last_end:                 
+                partitions += 1
+                last_end = i + 1
+            
+            last_pos[ord(s[i]) - ord('a')] = i + 1
+
+        return partitions