# Online Stock Span

Category

Monotonic Stack

Checkbox

Checkbox

Difficulty

Medium

Index

75

Key Ideas

The key idea to solve the LeetCode-75 problem is to use a monotonic stack to keep track of the stock span for each day.

Problem Number

901

Problem Summary

The problem "Online Stock Span" is about designing an algorithm to calculate the span of stock prices. The span of a stock on a particular day is defined as the maximum number of consecutive days in the past for which the price of the stock was less than or equal to the current day's price. A key pitfall to watch out for is handling large input sizes efficiently, as the brute force approach may not be optimal.

Solution Summary

The best solution for the Online Stock Span problem in LeetCode-75 curated list is to use a monotonic stack approach. This involves maintaining a stack of pairs, where each pair consists of the stock price and the span (number of consecutive days the price is less than or equal to the current day's price).
To calculate the span for a given day, we pop elements from the stack that have prices less than or equal to the current day's price. The span is then updated by adding the popped elements' spans. Finally, we push the current day's price and the updated span onto the stack.
This approach ensures efficient computation of the stock span for each day, as we only need to consider the relevant previous prices and spans in the stack.

Tags

Stack

Design

Monotonic Stack