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LEETFLIX

Count Bowl Subarrays

MediumArrayStackMono stack
Solve on LeetCode

Medium · stack solution for Count Bowl Subarrays. Python, Go, and a step-by-step animation.

01

Problem

Read the prompt, flip through the examples, then steal the idea.

LeetCode 3676. Count Bowl Subarrays. The copyrighted prompt is on LeetCode. This page is a working stack solution for this problem: editable input, Python, Go, and a step-by-step animation.

Constraints

  • —Player inputs are capped so the animation stays readable.
  • —Match LeetCode's own constraints when you submit there.

Examples

Input

s =
()[]{}

Output

true

Every closer matches the current top. The stack ends empty.

02

Solution

Python and Go. The walkthrough below runs this same code.

Approach 1Optimal▶ Animated

Count Bowl Subarrays — stack

Push openers; a closer is legal only if it matches the current top. Built for LeetCode 3676. Count Bowl Subarrays.

The stack is the nest of brackets that are still open. A mismatch or a leftover opener at the end is an immediate no.

Algorithm

  1. On an opener, push.
  2. On a closer, the top must be its partner — otherwise reject.
  3. Return true only if the stack is empty at the end.
Time
O(n)
Space
O(n)
Solution.py
class Solution:    def countBowlSubarrays(self, s: str) -> bool:        pairs = {")": "(", "]": "[", "}": "{"}        stack: list[str] = []        for ch in s:            if ch in pairs:                if not stack or stack[-1] != pairs[ch]:                    return False                stack.pop()            else:                stack.append(ch)        return not stack
Watch this run

03

Interactive walkthrough

Playing “Count Bowl Subarrays — stack”. Edit the input, hit Run, then scrub.

Approach: Count Bowl Subarrays — stack

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