Add Solution.py for 0421.Maximum XOR of Two Numbers in an Array

Author: Hinsteny

solution/0421.Maximum XOR of Two Numbers in an Array/Solution.py

@@ -0,0 +1,19 @@
+class Solution:
+    def findMaximumXOR(self, nums: List[int]) -> int:
+        max = 0
+        mask = 0
+        for i in range(30, -1, -1):
+            current = 1 << i
+            # 期望的二进制前缀
+            mask = mask ^ current
+            # 在当前前缀下, 数组内的前缀位数所有情况集合
+            _set = set()
+            for num in nums:
+                _set.add(num & mask)
+            # 期望最终异或值的从右数第i位为1, 再根据异或运算的特性推算假设是否成立
+            flag = max | current
+            for prefix in _set:
+                if prefix ^ flag in _set:
+                    max = flag
+                    break
+        return max

solution/README.md

@@ -768,7 +768,8 @@
 │   └── Solution.java
 ├── 0421.Maximum XOR of Two Numbers in an Array
 │   ├── README.md
-│   └── Solution.java
+│   ├── Solution.java
+│   └── Solution.py
 ├── 0423.Reconstruct Original Digits from English
 │   └── Solution.cpp
 ├── 0427.Construct Quad Tree