low to the minimum bloom day and high to the maximum bloom day.low is less than or equal to high, do the following:
a. Calculate mid as the average of low and high.
b. Check if it's possible to make m bouquets by day mid.
c. If it is possible, update high to mid - 1 (we will look for a smaller number of days).
d. If it is not possible, update low to mid + 1 (we need more days).m bouquets can be made, return that day. Otherwise, return -1 if no such day exists.