Online Stock Span — LeetCode 901 Python Solution

The problem

Design an algorithm that collects daily price quotes for some stock and returns the span of that stock's price for the current day. The span of the stock's price in one day is the maximum number of consecutive days (starting from that day and going backward) for which the stock price was less than or equal to the price of that day.

Example

Input

["StockSpanner", "next", "next", "next", "next", "next", "next", "next"]

Output

[null, 1, 1, 1, 2, 1, 4, 6]

Explanation

StockSpanner stockSpanner = new StockSpanner();

Python solution

class StockSpanner:
    def __init__(self):
        self.stk = []

    def next(self, price: int) -> int:
        cnt = 1
        while self.stk and self.stk[-1][0] <= price:
            cnt += self.stk.pop()[1]
        self.stk.append((price, cnt))
        return cnt


# Your StockSpanner object will be instantiated and called as such:
# obj = StockSpanner()
# param_1 = obj.next(price)

Complexity

Pattern: Stack

When the most recent unresolved thing is the one that matters, use a stack. LeetCode 901. Online Stock Span is filed here because LeetCode tags it Stack, 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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