maximal Rectangle

const maximalRectangle = (matrix) => {
  if (!matrix.length || !matrix[0].length) return 0;
  const height = matrix.length;
  const width = matrix[0].length;
  const lefts = matrix[0].map(() => 0);
  const rights = matrix[0].map(() => width);
  const heights = lefts.slice();
  let max = 0;
  for (let row = 0; row < height; row++) {
    let left = 0;
    let right = width;
    for (let i = 0; i < width; i++) {
      if (matrix[row][i] === '1') {
        lefts[i] = Math.max(left, lefts[i]);
        heights[i]++;
      } else {
        lefts[i] = heights[i] = 0;
        left = i + 1
      }

      const rightIdx = width - 1 - i;
      if (matrix[row][rightIdx] === '1') {
        rights[rightIdx] = Math.min(right, rights[rightIdx])
      } else {
        rights[rightIdx] = width;
        right = rightIdx;
      }
    }
    for (let i = 0; i < width; i++) {
      max = Math.max(max,(rights[i] - lefts[i]) * heights[i]);
    }
  }
  return max
}