LeetNode

A small Python 3.5+ library to make debugging LeetCode binary tree, linked list and matrix problems more convenient.

Binary Trees

from leetnode import TreeNode, build_btree

Creating a binary tree node

btree_node = TreeNode('val')

Creating a binary tree from a list

btree1 = build_btree([3, 9, 20, 8, 16, 15, 7, 1, 2, None, None, 3, None, None, None, None, None, 12])

or

btree2 = TreeNode.from_list(['a', 'b', 'cd', None, 'ef', 'gh', 'i', None, None, None, None, 'jkl', 'mn', 'o'])

or, from a JSON string

btree3 = TreeNode.from_list('[1, null, 555555, null, 43, 1]')

Printing a list representation of a binary tree

>>> print(btree1)
[3, 9, 20, 8, 16, 15, 7, 1, 2, None, None, 3, None, None, None, None, None, 12]

>>> print(btree2)
['a', 'b', 'cd', None, 'ef', 'gh', 'i', None, None, None, None, 'jkl', 'mn', 'o']

>>> print(btree3)
[1, None, 555555, None, 43, 1]

Printing a tree representation of a binary tree

>>> print(btree1.tree_string())
           ___3_____
          /         \
    _____9          _20
   /      \        /   \
  8___     16     15    7
 /    \          /
1     _2        3
     /
    12

>>> print(btree2.tree_string())
   ______'a'______
  /               \
'b'_            __'cd'___________
    \          /                 \
    'ef'     'gh'              __'i'_
                              /      \
                          _'jkl'     'mn'
                         /
                       'o'

>>> print(btree3.tree_string())
1__
   \
  555555__
          \
           43
          /
         1

Linked Lists

from leetnode import ListNode, build_linked_list

Creating a linked list node

list_node = ListNode('val')

Creating a linked list from a list

llist1 = build_linked_list(['a', 'b', 'c', 'd'])

or

llist2 = ListNode.from_list([1, 2, 3, 4, 5])

or, from a JSON string

llist3 = ListNode.from_list('["e", "f", "g", "h"]')

Printing a linked list

>>> print(llist1)
['a' -> 'b' -> 'c' -> 'd']

>>> print(llist2)
[1 -> 2 -> 3 -> 4 -> 5]

>>> print(llist3)
['e' -> 'f' -> 'g' -> 'h']

Iterating over a linked list

>>> for node in llist1:
...     print(node.val + node.next.val if node.next is not None else node.val)
...
ab
bc
cd
d

Matrices

Printing a matrix

>>> mat1 = [[1.2, 2.33, 3.0], [4.5, 6.7777, 8], [9.0, 10.98, 111.42]]
>>> mat2 = [[3, 0, 8, 4], [2, 2340, 5, 7], [97, 432, 6, 3], [0, 3, 1, 13]]
>>> mat3 = mat3 = '[["a", "b", "ccc"], ["dd", "e", "ff"], ["g", "h", "i"]]'

>>> print(matrix_to_string(mat1))
[ [ 1.2   , 2.33  , 3.0    ],
  [ 4.5   , 6.7777, 8      ],
  [ 9.0   , 10.98 , 111.42 ] ]

>>> print(matrix_to_string(mat2))
[ [    3,    0,    8,    4 ],
  [    2, 2340,    5,    7 ],
  [   97,  432,    6,    3 ],
  [    0,    3,    1,   13 ] ]

>>> print(matrix_to_string(mat3))
[ [ 'a'  , 'b'  , 'ccc' ],
  [ 'dd' , 'e'  , 'ff'  ],
  [ 'g'  , 'h'  , 'i'   ] ]