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hello-algo/en/codes/python/chapter_computational_complexity/iteration.py
Yudong Jin 14c314c08c Retranslate the complete English edition from Simplified Chinese (#2010)
* Retranslate the complete English edition from Simplified Chinese

* Polish three English explanations after reader-focused review
2026-10-31 03:35:51 +08:00

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1.4 KiB
Python

"""
File: iteration.py
Created Time: 2023-08-24
Author: krahets (krahets@163.com)
"""
def for_loop(n: int) -> int:
"""for loop"""
res = 0
# Sum 1, 2, ..., n-1, n in a loop
for i in range(1, n + 1):
res += i
return res
def while_loop(n: int) -> int:
"""while loop"""
res = 0
i = 1 # Initialize the loop control variable
# Sum 1, 2, ..., n-1, n in a loop
while i <= n:
res += i
i += 1 # Update the loop control variable
return res
def while_loop_ii(n: int) -> int:
"""while loop (two updates)"""
res = 0
i = 1 # Initialize the loop control variable
# Sum 1, 4, 10, ... in a loop
while i <= n:
res += i
# Update the loop control variable
i += 1
i *= 2
return res
def nested_for_loop(n: int) -> str:
"""Nested for loops"""
res = ""
# Loop over i = 1, 2, ..., n-1, n
for i in range(1, n + 1):
# Loop over j = 1, 2, ..., n-1, n
for j in range(1, n + 1):
res += f"({i}, {j}), "
return res
"""Driver code"""
if __name__ == "__main__":
n = 5
res = for_loop(n)
print(f"\nSum from the for loop: res = {res}")
res = while_loop(n)
print(f"\nSum from the while loop: res = {res}")
res = while_loop_ii(n)
print(f"\nSum from the while loop (two updates): res = {res}")
res = nested_for_loop(n)
print(f"\nTraversal from the nested for loops: {res}")