mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-10-06 05:39:30 +00:00
4b79d771cd
* Add more ruff rules * Add more ruff rules * pre-commit: Update ruff v0.0.269 -> v0.0.270 * Apply suggestions from code review * Fix doctest * Fix doctest (ignore whitespace) * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com> Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
45 lines
1.2 KiB
Python
45 lines
1.2 KiB
Python
"""
|
|
The nested brackets problem is a problem that determines if a sequence of
|
|
brackets are properly nested. A sequence of brackets s is considered properly nested
|
|
if any of the following conditions are true:
|
|
|
|
- s is empty
|
|
- s has the form (U) or [U] or {U} where U is a properly nested string
|
|
- s has the form VW where V and W are properly nested strings
|
|
|
|
For example, the string "()()[()]" is properly nested but "[(()]" is not.
|
|
|
|
The function called is_balanced takes as input a string S which is a sequence of
|
|
brackets and returns true if S is nested and false otherwise.
|
|
"""
|
|
|
|
|
|
def is_balanced(s):
|
|
stack = []
|
|
open_brackets = set({"(", "[", "{"})
|
|
closed_brackets = set({")", "]", "}"})
|
|
open_to_closed = {"{": "}", "[": "]", "(": ")"}
|
|
|
|
for i in range(len(s)):
|
|
if s[i] in open_brackets:
|
|
stack.append(s[i])
|
|
|
|
elif s[i] in closed_brackets and (
|
|
len(stack) == 0 or (len(stack) > 0 and open_to_closed[stack.pop()] != s[i])
|
|
):
|
|
return False
|
|
|
|
return len(stack) == 0
|
|
|
|
|
|
def main():
|
|
s = input("Enter sequence of brackets: ")
|
|
if is_balanced(s):
|
|
print(s, "is balanced")
|
|
else:
|
|
print(s, "is not balanced")
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|