Function fillStack

javascript/0084-largest-rectangle-in-histogram.js:111–134

(heights, stack = [], maxArea = 0)

};

const fillStack = (heights, stack = [], maxArea = 0) => {
    for (let index = 0; index < heights.length; index++) {
        /* Time O(N + N) */
        let start = index;

        const isCurrHeightLess = ([prevIndex, prevHeight], currHeight) =>
            currHeight < prevHeight;
        const canShrink = () =>
            isCurrHeightLess(stack[stack.length - 1], heights[index]);
        while (stack.length && canShrink()) {
            /* Time O(N + N) */
            const [_index, _height] = stack.pop();
            const width = index - _index;
            const area = _height * width;

            maxArea = Math.max(maxArea, area);
            start = _index;
        }

        stack.push([start, heights[index]]); /* Space O(N) */
    }

    return { stack, maxArea };
};

const getMaxArea = (heights, stack, maxArea) => {
    for (const [index, height] of stack) {