mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-30 16:31:08 +00:00
8bd4ca67be
* updating DIRECTORY.md
* chore(all-subsequence): added type hints [HACKTOBER-FEST]
* updating DIRECTORY.md
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
47 lines
1.2 KiB
Python
47 lines
1.2 KiB
Python
from typing import Any, List
|
|
|
|
"""
|
|
In this problem, we want to determine all possible subsequences
|
|
of the given sequence. We use backtracking to solve this problem.
|
|
|
|
Time complexity: O(2^n),
|
|
where n denotes the length of the given sequence.
|
|
"""
|
|
|
|
|
|
def generate_all_subsequences(sequence: List[Any]) -> None:
|
|
create_state_space_tree(sequence, [], 0)
|
|
|
|
|
|
def create_state_space_tree(
|
|
sequence: List[Any], current_subsequence: List[Any], index: int
|
|
) -> None:
|
|
"""
|
|
Creates a state space tree to iterate through each branch using DFS.
|
|
We know that each state has exactly two children.
|
|
It terminates when it reaches the end of the given sequence.
|
|
"""
|
|
|
|
if index == len(sequence):
|
|
print(current_subsequence)
|
|
return
|
|
|
|
create_state_space_tree(sequence, current_subsequence, index + 1)
|
|
current_subsequence.append(sequence[index])
|
|
create_state_space_tree(sequence, current_subsequence, index + 1)
|
|
current_subsequence.pop()
|
|
|
|
|
|
"""
|
|
remove the comment to take an input from the user
|
|
|
|
print("Enter the elements")
|
|
sequence = list(map(int, input().split()))
|
|
"""
|
|
|
|
sequence = [3, 1, 2, 4]
|
|
generate_all_subsequences(sequence)
|
|
|
|
sequence = ["A", "B", "C"]
|
|
generate_all_subsequences(sequence)
|