2315 Count Asterisks

We are required to count the number of asterisks between two pairs of |. Think of a pair of | as a wall within which you cannot see anything, and you can see everything between two such walls.

Well, we are just applying the same logic. We have a boolean flag variable that toggles to the moment we enter a wall (pair of |). When that boolean flag is off, we don’t capture anything. Once it is on, we read for asterisks and return the total.

Code:

Python

class Solution:
    def countAsterisks(self, s: str) -> int:
        flag = True 
 
        res = 0
        for c in s:
            if c == '|':
                flag = not flag
            
            if flag and c == '*':
                res += 1
        
        return res

Big O Analysis

• Runtime

  The runtime complexity here is O(N) as since we would be iterating the array atleast once.

• Memory

  The memory usage is O(N) since we use a stack to keep track of characters.

— A

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