Merge branch 'youngyangyang04:master' into master

problems/0040.组合总和II.md

@@ -296,7 +296,7 @@ class Solution {
 }
 ```
 Python：
-```py
+```python
 class Solution:
     def combinationSum2(self, candidates: List[int], target: int) -> List[List[int]]:
         res = []

problems/0102.二叉树的层序遍历.md

@@ -93,10 +93,10 @@ class Solution:
         if not root:
             return []
 
-        quene = [root]
+        queue = [root]
         out_list = []
 
-        while quene:
+        while queue:
             length = len(queue)  
             in_list = []
             for _ in range(length):

problems/0344.反转字符串.md

@@ -210,7 +210,20 @@ var reverseString = function(s) {
 };
 ```
 
+Swift:
 
+```swift
+func reverseString(_ s: inout [Character]) {
+    var l = 0
+    var r = s.count - 1
+    while l < r {
+      	// 使用元祖
+        (s[l], s[r]) = (s[r], s[l])
+        l += 1
+        r -= 1
+    }
+}
+```