Optimize arrToTree function

in java, cpp, py, go, js, ts.

codes/python/chapter_tree/binary_search_tree.py

@@ -138,7 +138,7 @@ class BinarySearchTree:
 """ Driver Code """
 if __name__ == "__main__":
     # 初始化二叉搜索树
-    nums = list(range(1, 16))
+    nums = list(range(1, 16)) # [1, 2, ..., 15]
     bst = BinarySearchTree(nums=nums)
     print("\n初始化的二叉树为\n")
     print_tree(bst.root)

codes/python/chapter_tree/binary_tree.py

@@ -36,5 +36,5 @@ if __name__ == "__main__":
     print_tree(n1)
     # 删除结点
     n1.left = n2
-    print("\n删除结点 P 后\n");
+    print("\n删除结点 P 后\n")
     print_tree(n1)

codes/python/chapter_tree/binary_tree_bfs.py

@@ -32,7 +32,7 @@ def hier_order(root: TreeNode):
 if __name__ == "__main__":
     # 初始化二叉树
     # 这里借助了一个从数组直接生成二叉树的函数
-    root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7, None, None, None, None, None, None, None, None])
+    root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7])
     print("\n初始化二叉树\n")
     print_tree(root)
 

codes/python/chapter_tree/binary_tree_dfs.py

@@ -45,7 +45,7 @@ def post_order(root: typing.Optional[TreeNode]):
 if __name__ == "__main__":
     # 初始化二叉树
     # 这里借助了一个从数组直接生成二叉树的函数
-    root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7, None, None, None, None, None, None, None, None])
+    root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7])
     print("\n初始化二叉树\n")
     print_tree(root)
 

codes/python/include/binary_tree.py

@@ -26,39 +26,30 @@ class TreeNode:
 
 def list_to_tree(arr):
     """Generate a binary tree with a list
-
-    Args:
-        arr ([type]): [description]
-
-    Returns:
-        [type]: [description]
     """
     if not arr:
         return None
-    i = 1
-    root = TreeNode(int(arr[0]))
-    queue = collections.deque()
-    queue.append(root)
+    
+    i = 0
+    root = TreeNode(arr[0])
+    queue = collections.deque([root])
     while queue:
         node = queue.popleft()
+        i += 1
+        if i >= len(arr): break
         if arr[i] != None:
-            node.left = TreeNode(int(arr[i]))
+            node.left = TreeNode(arr[i])
             queue.append(node.left)
         i += 1
+        if i >= len(arr): break
         if arr[i] != None:
-            node.right = TreeNode(int(arr[i]))
+            node.right = TreeNode(arr[i])
             queue.append(node.right)
-        i += 1
+            
     return root
 
 def tree_to_list(root):
     """Serialize a tree into an array
-
-    Args:
-        root ([type]): [description]
-
-    Returns:
-        [type]: [description]
     """    
     if not root: return []
     queue = collections.deque()
@@ -75,13 +66,6 @@ def tree_to_list(root):
 
 def get_tree_node(root, val):
     """Get a tree node with specific value in a binary tree
-
-    Args:
-        root ([type]): [description]
-        val ([type]): [description]
-
-    Returns:
-        [type]: [description]
     """    
     if not root:
         return