You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
hello-algo/en/codes/python/chapter_computational_compl.../space_complexity.py

91 lines
1.9 KiB

"""
File: space_complexity.py
Created Time: 2022-11-25
Author: krahets (krahets@163.com)
"""
import sys
from pathlib import Path
sys.path.append(str(Path(__file__).parent.parent))
from modules import ListNode, TreeNode, print_tree
def function() -> int:
"""Function"""
# Perform some operations
return 0
def constant(n: int):
"""Constant complexity"""
# Constants, variables, objects occupy O(1) space
a = 0
nums = [0] * 10000
node = ListNode(0)
# Variables in a loop occupy O(1) space
for _ in range(n):
c = 0
# Functions in a loop occupy O(1) space
for _ in range(n):
function()
def linear(n: int):
"""Linear complexity"""
# A list of length n occupies O(n) space
nums = [0] * n
# A hash table of length n occupies O(n) space
hmap = dict[int, str]()
for i in range(n):
hmap[i] = str(i)
def linear_recur(n: int):
"""Linear complexity (recursive implementation)"""
print("Recursive n =", n)
if n == 1:
return
linear_recur(n - 1)
def quadratic(n: int):
"""Quadratic complexity"""
# A two-dimensional list occupies O(n^2) space
num_matrix = [[0] * n for _ in range(n)]
def quadratic_recur(n: int) -> int:
"""Quadratic complexity (recursive implementation)"""
if n <= 0:
return 0
# Array nums length = n, n-1, ..., 2, 1
nums = [0] * n
return quadratic_recur(n - 1)
def build_tree(n: int) -> TreeNode | None:
"""Exponential complexity (building a full binary tree)"""
if n == 0:
return None
root = TreeNode(0)
root.left = build_tree(n - 1)
root.right = build_tree(n - 1)
return root
"""Driver Code"""
if __name__ == "__main__":
n = 5
# Constant complexity
constant(n)
# Linear complexity
linear(n)
linear_recur(n)
# Quadratic complexity
quadratic(n)
quadratic_recur(n)
# Exponential complexity
root = build_tree(n)
print_tree(root)