diff --git a/solution/0003.Longest Substring Without Repeating Characters/Solution.py b/solution/0003.Longest Substring Without Repeating Characters/Solution.py
new file mode 100644
index 0000000000000..fc699d1e46300
--- /dev/null
+++ b/solution/0003.Longest Substring Without Repeating Characters/Solution.py	
@@ -0,0 +1,12 @@
+class Solution:
+    def lengthOfLongestSubstring(self, s: str):
+        max = 0
+        length = len(s)
+        substr = ""
+        for i in range(0, length):
+            index = substr.find(s[i])
+            if index > -1:
+                substr = substr[index + 1:]
+            substr += s[i]
+            max = (max if (max > len(substr)) else len(substr))
+        return max
\ No newline at end of file
diff --git a/solution/0421.Maximum XOR of Two Numbers in an Array/Solution.py b/solution/0421.Maximum XOR of Two Numbers in an Array/Solution.py
new file mode 100644
index 0000000000000..be25295ac40a1
--- /dev/null
+++ b/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
\ No newline at end of file
diff --git a/solution/README.md b/solution/README.md
index 706764aa96042..f8583b6b8777e 100644
--- a/solution/README.md
+++ b/solution/README.md
@@ -25,7 +25,8 @@
 │   ├── README.md
 │   ├── Solution.go
 │   ├── Solution.java
-│   └── Solution.js
+│   ├── Solution.js
+│   └── Solution.py
 ├── 0004.Median of Two Sorted Arrays
 │   ├── README.md
 │   ├── Solution.cpp
@@ -767,7 +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