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lowest_common_ancestor.py static type checking (#2329)

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* adding static type checking to basic_binary_tree.py

* Add static type checking to functions with None return type

* Applying code review comments

* Added missing import statement

* fix spaciing

* "cleaned up depth_of_tree"

* Add doctests and then streamline display() and is_full_binary_tree()

* added static typing to lazy_segment_tree.py

* added missing import statement

* modified variable names for left and right elements

* added static typing to lowest_common_ancestor.py

* fixed formatting

* modified files to meet style guidelines, edited docstrings and added some doctests

* added and fixed doctests in lazy_segment_tree.py

* fixed errors in doctests

Co-authored-by: Christian Clauss <cclauss@me.com>
This commit is contained in:
kanthuc
2020-08-20 21:54:34 -07:00
committed by GitHub
parent d3199da000
commit 2eaacee7b4
2 changed files with 107 additions and 50 deletions
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56
data_structures/binary_tree/lowest_common_ancestor.py
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@ -2,17 +2,29 @@
# https://en.wikipedia.org/wiki/Breadth-first_search
import queue
from typing import Dict, List, Tuple
def swap(a, b):
def swap(a: int, b: int) -> Tuple[int, int]:
"""
Return a tuple (b, a) when given two integers a and b
>>> swap(2,3)
(3, 2)
>>> swap(3,4)
(4, 3)
>>> swap(67, 12)
(12, 67)
"""
a ^= b
b ^= a
a ^= b
return a, b
# creating sparse table which saves each nodes 2^i-th parent
def creatSparse(max_node, parent):
def create_sparse(max_node: int, parent: List[List[int]]) -> List[List[int]]:
"""
creating sparse table which saves each nodes 2^i-th parent
"""
j = 1
while (1 << j) < max_node:
for i in range(1, max_node + 1):
@ -22,7 +34,9 @@ def creatSparse(max_node, parent):
# returns lca of node u,v
def LCA(u, v, level, parent):
def lowest_common_ancestor(
u: int, v: int, level: List[int], parent: List[List[int]]
) -> List[List[int]]:
# u must be deeper in the tree than v
if level[u] < level[v]:
u, v = swap(u, v)
@ -42,10 +56,18 @@ def LCA(u, v, level, parent):
# runs a breadth first search from root node of the tree
# sets every nodes direct parent
# parent of root node is set to 0
# calculates depth of each node from root node
def bfs(level, parent, max_node, graph, root=1):
def breadth_first_search(
level: List[int],
parent: List[List[int]],
max_node: int,
graph: Dict[int, int],
root=1,
) -> Tuple[List[int], List[List[int]]]:
"""
sets every nodes direct parent
parent of root node is set to 0
calculates depth of each node from root node
"""
level[root] = 0
q = queue.Queue(maxsize=max_node)
q.put(root)
@ -59,7 +81,7 @@ def bfs(level, parent, max_node, graph, root=1):
return level, parent
def main():
def main() -> None:
max_node = 13
# initializing with 0
parent = [[0 for _ in range(max_node + 10)] for _ in range(20)]
@ -80,14 +102,14 @@ def main():
12: [],
13: [],
}
level, parent = bfs(level, parent, max_node, graph, 1)
parent = creatSparse(max_node, parent)
print("LCA of node 1 and 3 is: ", LCA(1, 3, level, parent))
print("LCA of node 5 and 6 is: ", LCA(5, 6, level, parent))
print("LCA of node 7 and 11 is: ", LCA(7, 11, level, parent))
print("LCA of node 6 and 7 is: ", LCA(6, 7, level, parent))
print("LCA of node 4 and 12 is: ", LCA(4, 12, level, parent))
print("LCA of node 8 and 8 is: ", LCA(8, 8, level, parent))
level, parent = breadth_first_search(level, parent, max_node, graph, 1)
parent = create_sparse(max_node, parent)
print("LCA of node 1 and 3 is: ", lowest_common_ancestor(1, 3, level, parent))
print("LCA of node 5 and 6 is: ", lowest_common_ancestor(5, 6, level, parent))
print("LCA of node 7 and 11 is: ", lowest_common_ancestor(7, 11, level, parent))
print("LCA of node 6 and 7 is: ", lowest_common_ancestor(6, 7, level, parent))
print("LCA of node 4 and 12 is: ", lowest_common_ancestor(4, 12, level, parent))
print("LCA of node 8 and 8 is: ", lowest_common_ancestor(8, 8, level, parent))
if __name__ == "__main__":