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Commit 18cdbc4

Browse files
binary_search_traversals.py made memory-friendly using generators. Fixes TheAlgorithms#8725 completely. (TheAlgorithms#9237)
* Made binary tree memory-friendly using generators based travels. Fixes TheAlgorithms#8725 * Made binary tree memory-friendly using generators based travels. Fixes TheAlgorithms#8725 * Fixed pre-commit errors
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‎data_structures/binary_tree/binary_tree_traversals.py‎

Lines changed: 23 additions & 34 deletions
Original file line numberDiff line numberDiff line change
@@ -1,9 +1,8 @@
11
from __future__ import annotations
22

33
from collections import deque
4-
from collections.abc import Generator, Sequence
4+
from collections.abc import Generator
55
from dataclasses import dataclass
6-
from typing import Any
76

87

98
# https://en.wikipedia.org/wiki/Tree_traversal
@@ -94,96 +93,86 @@ def height(root: Node | None) -> int:
9493
return (max(height(root.left), height(root.right)) + 1) if root else 0
9594

9695

97-
def level_order(root: Node | None) -> Sequence[Node| None]:
96+
def level_order(root: Node | None) -> Generator[int, None, None]:
9897
"""
9998
Returns a list of nodes value from a whole binary tree in Level Order Traverse.
10099
Level Order traverse: Visit nodes of the tree level-by-level.
101100
"""
102-
output: list[Any] = []
103101

104102
if root is None:
105-
returnoutput
103+
return
106104

107105
process_queue = deque([root])
108106

109107
while process_queue:
110108
node = process_queue.popleft()
111-
output.append(node.data)
109+
yieldnode.data
112110

113111
if node.left:
114112
process_queue.append(node.left)
115113
if node.right:
116114
process_queue.append(node.right)
117-
return output
118115

119116

120117
def get_nodes_from_left_to_right(
121118
root: Node | None, level: int
122-
) -> Sequence[Node| None]:
119+
) -> Generator[int, None, None]:
123120
"""
124121
Returns a list of nodes value from a particular level:
125122
Left to right direction of the binary tree.
126123
"""
127-
output: list[Any] = []
128124

129-
def populate_output(root: Node | None, level: int) -> None:
125+
def populate_output(root: Node | None, level: int) -> Generator[int, None, None]:
130126
if not root:
131127
return
132128
if level == 1:
133-
output.append(root.data)
129+
yieldroot.data
134130
elif level > 1:
135-
populate_output(root.left, level - 1)
136-
populate_output(root.right, level - 1)
131+
yieldfrompopulate_output(root.left, level - 1)
132+
yieldfrompopulate_output(root.right, level - 1)
137133

138-
populate_output(root, level)
139-
return output
134+
yield from populate_output(root, level)
140135

141136

142137
def get_nodes_from_right_to_left(
143138
root: Node | None, level: int
144-
) -> Sequence[Node| None]:
139+
) -> Generator[int, None, None]:
145140
"""
146141
Returns a list of nodes value from a particular level:
147142
Right to left direction of the binary tree.
148143
"""
149-
output: list[Any] = []
150144

151-
def populate_output(root: Node | None, level: int) -> None:
145+
def populate_output(root: Node | None, level: int) -> Generator[int, None, None]:
152146
if root is None:
153147
return
154148
if level == 1:
155-
output.append(root.data)
149+
yieldroot.data
156150
elif level > 1:
157-
populate_output(root.right, level - 1)
158-
populate_output(root.left, level - 1)
151+
yieldfrompopulate_output(root.right, level - 1)
152+
yieldfrompopulate_output(root.left, level - 1)
159153

160-
populate_output(root, level)
161-
return output
154+
yield from populate_output(root, level)
162155

163156

164-
def zigzag(root: Node | None) -> Sequence[Node|None] |list[Any]:
157+
def zigzag(root: Node | None) -> Generator[int, None, None]:
165158
"""
166159
ZigZag traverse:
167160
Returns a list of nodes value from left to right and right to left, alternatively.
168161
"""
169162
if root is None:
170-
return []
171-
172-
output: list[Sequence[Node | None]] = []
163+
return
173164

174165
flag = 0
175166
height_tree = height(root)
176167

177168
for h in range(1, height_tree + 1):
178169
if not flag:
179-
output.append(get_nodes_from_left_to_right(root, h))
170+
yieldfromget_nodes_from_left_to_right(root, h)
180171
flag = 1
181172
else:
182-
output.append(get_nodes_from_right_to_left(root, h))
173+
yieldfromget_nodes_from_right_to_left(root, h)
183174
flag = 0
184175

185-
return output
186-
187176

188177
def main() -> None: # Main function for testing.
189178
# Create binary tree.
@@ -198,15 +187,15 @@ def main() -> None: # Main function for testing.
198187
print(f"Height of Tree: {height(root)}", "\n")
199188

200189
print("Complete Level Order Traversal: ")
201-
print(level_order(root), "\n")
190+
print(f"{list(level_order(root))}\n")
202191

203192
print("Level-wise order Traversal: ")
204193

205194
for level in range(1, height(root) + 1):
206-
print(f"Level {level}:", get_nodes_from_left_to_right(root, level=level))
195+
print(f"Level {level}:", list(get_nodes_from_left_to_right(root, level=level)))
207196

208197
print("\nZigZag order Traversal: ")
209-
print(zigzag(root))
198+
print(f"{list(zigzag(root))}")
210199

211200

212201
if __name__ == "__main__":

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