mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 21:41:08 +00:00
bc8df6de31
* [pre-commit.ci] pre-commit autoupdate updates: - [github.com/astral-sh/ruff-pre-commit: v0.2.2 → v0.3.2](https://github.com/astral-sh/ruff-pre-commit/compare/v0.2.2...v0.3.2) - [github.com/pre-commit/mirrors-mypy: v1.8.0 → v1.9.0](https://github.com/pre-commit/mirrors-mypy/compare/v1.8.0...v1.9.0) * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
44 lines
1.2 KiB
Python
44 lines
1.2 KiB
Python
"""
|
|
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.
|
|
"""
|
|
|
|
from __future__ import annotations
|
|
|
|
from typing import Any
|
|
|
|
|
|
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()
|
|
|
|
|
|
if __name__ == "__main__":
|
|
seq: list[Any] = [3, 1, 2, 4]
|
|
generate_all_subsequences(seq)
|
|
|
|
seq.clear()
|
|
seq.extend(["A", "B", "C"])
|
|
generate_all_subsequences(seq)
|