Merge pull request youngyangyang04#2562 from FEI120483/master

Update Python3

Author: youngyangyang04

problems/0151.翻转字符串里的单词.md

@@ -467,6 +467,13 @@ class Solution:
         # 将列表转换成字符串
         return " ".join(words)
 ```
+(版本三) 拆分字符串 + 反转列表
+```python
+class Solution:
+    def reverseWords(self, s):
+        words = s.split() #type(words) --- list
+        words = words[::-1] # 反转单词
+        return ' '.join(words) #列表转换成字符串
 
 ### Go：
 

problems/0455.分发饼干.md

@@ -206,8 +206,26 @@ class Solution:
 
 ```
 
-### Go
+栈 大饼干优先
+```python
+from collecion import deque
+class Solution:
+    def findContentChildren(self, g: List[int], s: List[int]) -> int:
+      #思路,饼干和孩子按从大到小排序,依次从栈中取出，若满足条件result += 1 否则将饼干栈顶元素重新返回 
+        result = 0
+        queue_g = deque(sorted(g, reverse = True))
+        queue_s = deque(sorted(s, reverse = True))
+        while queue_g and queue_s:
+            child = queue_g.popleft()
+            cookies = queue_s.popleft()
+            if child <= cookies:
+                result += 1
+            else:
+                queue_s.appendleft(cookies)
+        return result
+```
 
+### Go
 ```golang
 //排序后，局部最优
 func findContentChildren(g []int, s []int) int {

problems/0700.二叉搜索树中的搜索.md

@@ -262,6 +262,26 @@ class Solution:
         return None
 ```
 
+(方法三) 栈-遍历
+```python
+class Solution:
+    def searchBST(self, root: TreeNode, val: int) -> TreeNode:
+        stack = [root]
+        while stack:
+            node = stack.pop()
+            # 根据TreeNode的定义
+            # node携带有三类信息 node.left/node.right/node.val
+            # 找到val直接返回node 即是找到了该节点为根的子树
+            # 此处node.left/node.right/val的前后顺序可打乱
+            if node.val == val: 
+                return node
+            if node.right:
+                stack.append(node.right)
+            if node.left:
+                stack.append(node.left)
+        return None
+```
+
 
 ### Go 
 

problems/0977.有序数组的平方.md

@@ -178,6 +178,24 @@ class Solution:
         return sorted(x*x for x in nums)
 ```
 
+```Python
+(版本四) 双指针+ 反转列表
+class Solution:
+    def sortedSquares(self, nums: List[int]) -> List[int]:
+        #根据list的先进排序在先原则
+        #将nums的平方按从大到小的顺序添加进新的list
+        #最后反转list
+        new_list = []
+        left, right = 0 , len(nums) -1
+        while left <= right:
+            if abs(nums[left]) <= abs(nums[right]):
+                new_list.append(nums[right] ** 2)
+                right -= 1
+            else:
+                new_list.append(nums[left] ** 2)
+                left += 1
+        return new_list[::-1]
+
 ### Go：
 
 ```Go

problems/kamacoder/0055.右旋字符串.md

@@ -222,6 +222,13 @@ s = s[len(s)-k:] + s[:len(s)-k]
 print(s)
 ```
 
+```Python 切片法
+k = int(input())
+s = input()
+
+print(s[-k:] + s[:-k])
+```
+
 ### Go：
 ```go
 package main