Valid Parentheses ()[]{}
Validates balanced brackets '()', '{}', '[]' using a stack to guarantee every closing tag matches the nearest open tag.
Live loop — open the studio to scrub, add your own array, or race it in Battle Arena.
Asked in interviews at
Reference implementation (Python)
def is_valid(s: str) -> bool:
stack = []
mapping = {')': '(', '}': '{', ']': '['}
for char in s:
if char in '({[':
stack.append(char)
elif char in ')}]':
if not stack or stack[-1] != mapping[char]:
return False
stack.pop()
return len(stack) == 0Embed this visualization
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<iframe src="/embed/valid-parentheses" width="100%" height="380" style="border:1px solid #e6e8ec;border-radius:14px" loading="lazy" title="3D algorithm visualization by CodeWithMunnaX"></iframe>Frequently asked
What is the time and space complexity of Valid Parentheses ()[]{}?
Valid Parentheses ()[]{} runs in O(n) time and O(n) auxiliary space.
Is the Valid Parentheses ()[]{} visualizer free?
The core 3D visualizer, Web Audio chimes and step intuition are free. A one-time ₹49 Pro Pass unlocks advanced algorithms, large custom arrays, Battle Arena and reel export.
Which companies ask Valid Parentheses ()[]{} in interviews?
Valid Parentheses ()[]{} shows up in interviews at Meta, Google, Amazon, Bloomberg.
How does the 3D visualization of Valid Parentheses ()[]{} work?
Each array value becomes a 3D pillar whose height maps to its value. Comparisons glow amber, swaps flash red, and settled elements lock green while a floating pointer badge tracks the active index — synchronized line-by-line with the Python code.