#84 - Largest Rectangle in Histogram

Hard • View on LeetCode • View on GitHub

Problem Description

Given an array of integers heights representing the histogram's bar height where the width of each bar is 1, return the area of the largest rectangle in the histogram.

Solution

/**
 * @param {number[]} heights
 * @return {number}
 */
var largestRectangleArea = function(heights) {
  const entries = [...heights, 0];
  const stack = [];
  let area = 0;

  for (let i = 0; i < entries.length; i++) {
    let updatedHeight = i;

    while (stack.length && stack[stack.length - 1][1] > entries[i]) {
      const [x, y] = stack.pop();
      area = Math.max(area, (i - x) * y);
      updatedHeight = x;
    }

    stack.push([updatedHeight, entries[i]]);
  }

  return area;
};