Rearrange the chapters.

Start to translate codes from Java to Python.

codes/python/include/__init__.py

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+import copy
+import math
+import random
+import functools
+import collections
+from typing import List
+from .linked_list import ListNode, list_to_linked_list, linked_list_to_list, get_list_node
+from .binary_tree import TreeNode, list_to_tree, tree_to_list, get_tree_node
+from .print_util import print_matrix, print_linked_list, print_tree

codes/python/include/binary_tree.py

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+'''
+File: binary_tree.py
+Created Time: 2021-12-11
+Author: Krahets (krahets@163.com)
+'''
+
+import collections
+
+class TreeNode:
+    """Definition for a binary tree node
+    """    
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+def list_to_tree(arr):
+    """Generate a binary tree with a list
+
+    Args:
+        arr ([type]): [description]
+
+    Returns:
+        [type]: [description]
+    """
+    if not arr:
+        return
+    i = 1
+    root = TreeNode(int(arr[0]))
+    queue = collections.deque()
+    queue.append(root)
+    while queue:
+        node = queue.popleft()
+        if arr[i] != None:
+            node.left = TreeNode(int(arr[i]))
+            queue.append(node.left)
+        i += 1
+        if arr[i] != None:
+            node.right = TreeNode(int(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()
+    queue.append(root)
+    res = []
+    while queue:
+        node = queue.popleft()
+        if node:
+            res.append(node.val)
+            queue.append(node.left)
+            queue.append(node.right)
+        else: res.append(None)
+    return res
+
+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
+    if root.val == val:
+        return root
+    left = get_tree_node(root.left, val)
+    right = get_tree_node(root.right, val)
+    return left if left else right

codes/python/include/linked_list.py

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+'''
+File: linked_list.py
+Created Time: 2021-12-11
+Author: Krahets (krahets@163.com)
+'''
+
+class ListNode:
+    """Definition for a singly-linked list node
+    """    
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+def list_to_linked_list(arr):
+    """Generate a linked list with a list
+
+    Args:
+        arr ([type]): [description]
+
+    Returns:
+        [type]: [description]
+    """    
+    dum = head = ListNode(0)
+    for a in arr:
+        node = ListNode(a)
+        head.next = node
+        head = head.next
+    return dum.next
+
+def linked_list_to_list(head):
+    """Serialize a linked list into an array
+
+    Args:
+        head ([type]): [description]
+
+    Returns:
+        [type]: [description]
+    """    
+    arr = []
+    while head:
+        arr.append(head.val)
+        head = head.next
+    return arr
+
+def get_list_node(head, val):
+    """Get a list node with specific value from a linked list
+
+    Args:
+        head ([type]): [description]
+        val ([type]): [description]
+
+    Returns:
+        [type]: [description]
+    """    
+    while head and head.val != val:
+        head = head.next
+    return head

codes/python/include/print_util.py

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+'''
+File: print_util.py
+Created Time: 2021-12-11
+Author: Krahets (krahets@163.com)
+'''
+
+from .binary_tree import TreeNode, tree_to_list
+from .linked_list import ListNode, linked_list_to_list
+
+def print_matrix(mat):
+    """Print a matrix
+
+    Args:
+        mat ([type]): [description]
+    """    
+    pstr = []
+    for arr in mat:
+        pstr.append('  ' + str(arr))
+
+    print('[\n' + ',\n'.join(pstr) + '\n]')
+
+def print_linked_list(head):
+    """Print a linked list
+
+    Args:
+        head ([type]): [description]
+    """    
+    arr = linked_list_to_list(head)
+    print(' -> '.join([str(a) for a in arr]))
+
+
+class Trunk:
+    def __init__(self, prev=None, str=None):
+        self.prev = prev
+        self.str = str
+ 
+def showTrunks(p):
+    if p is None:
+        return
+    showTrunks(p.prev)
+    print(p.str, end='')
+ 
+def print_tree(root, prev=None, isLeft=False):
+    """Print a binary tree
+       This tree printer is borrowed from TECHIE DELIGHT
+       https://www.techiedelight.com/c-program-print-binary-tree/
+    Args:
+        root ([type]): [description]
+        prev ([type], optional): [description]. Defaults to None.
+        isLeft (bool, optional): [description]. Defaults to False.
+    """
+    if root is None:
+        return
+ 
+    prev_str = '    '
+    trunk = Trunk(prev, prev_str)
+    print_tree(root.right, trunk, True)
+ 
+    if prev is None:
+        trunk.str = '———'
+    elif isLeft:
+        trunk.str = '/———'
+        prev_str = '   |'
+    else:
+        trunk.str = '\———'
+        prev.str = prev_str
+ 
+    showTrunks(trunk)
+    print(' ' + str(root.val))
+    if prev:
+        prev.str = prev_str
+    trunk.str = '   |'
+    print_tree(root.left, trunk, False)