Add: Solution.py

solution/1900-1999/1938.Maximum Genetic Difference Query/Solution.py

@@ -0,0 +1,79 @@
+from collections import defaultdict
+
+class TrieNode:
+    def __init__(self):
+        self.children = {}
+        self.count = 0
+
+class Trie:
+    def __init__(self):
+        self.root = TrieNode()
+
+    def insert(self, num):
+        node = self.root
+        for i in range(17, -1, -1):
+            bit = (num >> i) & 1
+            if bit not in node.children:
+                node.children[bit] = TrieNode()
+            node = node.children[bit]
+            node.count += 1
+
+    def remove(self, num):
+        node = self.root
+        for i in range(17, -1, -1):
+            bit = (num >> i) & 1
+            if bit in node.children:
+                node = node.children[bit]
+                node.count -= 1
+
+    def maxXOR(self, num):
+        node = self.root
+        max_xor = 0
+        for i in range(17, -1, -1):
+            bit = (num >> i) & 1
+            toggled_bit = 1 - bit
+            if toggled_bit in node.children and node.children[toggled_bit].count > 0:
+                max_xor |= (1 << i)
+                node = node.children[toggled_bit]
+            else:
+                node = node.children[bit]
+        return max_xor
+
+class Solution:
+    def maxGeneticDifference(self, parents, queries):
+        n = len(parents)
+
+        # Build the tree as an adjacency list
+        tree = defaultdict(list)
+        root = -1
+        for i in range(n):
+            if parents[i] == -1:
+                root = i
+            else:
+                tree[parents[i]].append(i)
+
+        # Group queries by the node
+        query_map = defaultdict(list)
+        for idx, (node, val) in enumerate(queries):
+            query_map[node].append((val, idx))
+
+        # Result array
+        res = [0] * len(queries)
+
+        # Trie to store and query the path genetic values
+        trie = Trie()
+
+        # Depth-first search to solve the queries
+        def dfs(node):
+            trie.insert(node)
+            if node in query_map:
+                for val, idx in query_map[node]:
+                    res[idx] = trie.maxXOR(val)
+            for child in tree[node]:
+                dfs(child)
+            trie.remove(node)
+
+        # Start DFS from the root
+        dfs(root)
+
+        return res