Number of Recent Calls — LeetCode 933 Python Solution

The problem

You have a RecentCounter class which counts the number of recent requests within a certain time frame. Implement the RecentCounter class: RecentCounter() Initializes the counter with zero recent requests.

Example

Input

["RecentCounter", "ping", "ping", "ping", "ping"]

Output

[null, 1, 2, 3, 3]

Explanation

RecentCounter recentCounter = new RecentCounter();

Python solution

class RecentCounter:
    def __init__(self):
        self.q = deque()

    def ping(self, t: int) -> int:
        self.q.append(t)
        while self.q[0] < t - 3000:
            self.q.popleft()
        return len(self.q)


# Your RecentCounter object will be instantiated and called as such:
# obj = RecentCounter()
# param_1 = obj.ping(t)

Complexity

Pattern: Stack

When the most recent unresolved thing is the one that matters, use a stack. LeetCode 933. Number of Recent Calls is filed here because LeetCode tags it Queue, which is the vocabulary this hub collects.

The stack guide has the Python template for the pattern and the 194 LeetCode problems that use it.

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