package q85

func maximalRectangle(matrix [][]byte) int {
	var maxArea int

	for row := range matrix {
		for col := range matrix[0] {
			matrix[row][col] -= '0'
			if matrix[row][col] == 0 {
				continue
			}

			if col > 0 {
				matrix[row][col] += matrix[row][col-1]
			}

			maxW := matrix[row][col]
			for i := 0; row-i >= 0; i++ {
				if matrix[row-i][col] == 0 {
					break
				}
				maxW = min(maxW, matrix[row-i][col])
				maxArea = max(maxArea, int(maxW)*(i+1))
			}
		}
	}

	return maxArea
}

var _ = maximalRectangle