Count Rectangles in Wall

gistfile1.txt

function reactanlgeCount(arr) {
  const stack = [];

  let count = 0;

  for (let i = 0; i < arr.length; i++) {
    const next = arr[i];

    while (stack.length && next < stack[stack.length - 1]) {
      stack.pop();
    }

    if (!(stack.length && stack[stack.length - 1] === next)) {
      stack.push(next);
      count++;
    }
  }

  return count;
}