Online Stock Span Medium 0 attempts
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Online Stock Span

Medium Stack&Queue LeetCode

Design a class that collects daily stock prices and returns the span — the number of consecutive days (including today) the price was <= today's price.

Example: prices = [100,80,60,70,60,75,85] → spans = [1,1,1,2,1,4,6]

Sample Input
—
Sample Output
—
Constraints
  • 1 <= price <= 10^5
  • At most 10^4 calls to next
Topics
Stack&Queue

Monotonic Stack

class StockSpanner {
  constructor() { this.stack = []; }
  next(price) {
    let span = 1;
    while (this.stack.length && this.stack[this.stack.length-1][0] <= price)
      span += this.stack.pop()[1];
    this.stack.push([price, span]);
    return span;
  }
}

Time: O(1) amortized | Space: O(n)

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