Count Asterisks — LeetCode 2315 Python Solution

The problem

You are given a string s, where every two consecutive vertical bars '|' are grouped into a pair. In other words, the 1st and 2nd '|' make a pair, the 3rd and 4th '|' make a pair, and so forth.

Example

Input

s = "l|*e*et|c**o|*de|"

Output

2

Explanation

The considered characters are underlined: "l|*e*et|c**o|*de|".

Python solution

class Solution:
    def countAsterisks(self, s: str) -> int:
        ans, ok = 0, 1
        for c in s:
            if c == "*":
                ans += ok
            elif c == "|":
                ok ^= 1
        return ans

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 2315. Count Asterisks is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.

The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.

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