Program to find minimum number of days to make m bouquets using Python

Suppose we have an array with integers called nums, we also have another two values m and k. Now, we need to make m bouquets. To make one bouquet we need k adjacent flowers from the garden. Here the garden consists of n different flowers, the ith flower will bloom in the bloomDay[i]. Each flower can be used inside only one bouquets. We have to find the minimum number of days need to wait to make m bouquets from the garden. If we cannot make m bouquets, then return -1.

So, if the input is like bloomDay = [5,5,5,5,10,5,5] m = 2 k = 3, then the output will be 10 because we need 2 (m = 2) bouquets and each should have 3 flowers.

• After day 5: [x, x, x, x, _, x, x], we can make one bouquet of the first three flowers that bloomed, but cannot make another bouquet

• After day 10: [x, x, x, x, x, x, x], Now we can make two bouquets in different ways.

To solve this, we will follow these steps −

• n := size of bloomDay

• if m * k > n, then

  • return -1

• Define a function possible() . This will take x

• count := 0, bouquets := 0

• for each d in bloomDay, do

  • if d <= x, then

    • count := count + 1

    • if count is same as k, then

      • bouquets := bouquets + 1

      • count := 0

  • otherwise,

    • count := 0

• return true if bouquets >= m, otherwise false

• From the main method do the following −

• left := 0, right := 1 + maximum of bloomDay

• while left < right, do

  • mid :=(left + right) /2

  • if possible(mid) is true, then

    • right := mid

  • otherwise,

    • left := mid + 1

• if possible(left) is true, then

  • return left

• otherwise return left + 1

Let us see the following implementation to get better understanding −

Example

def solve(bloomDay, m, k):
   n = len(bloomDay)
   if m * k > n:
      return -1
   def possible(x):
      count = 0
      bouquets = 0
      for d in bloomDay:
         if d <= x:
            count += 1
            if count == k:
               bouquets += 1
               count = 0
         else:
            count = 0
      return bouquets >= m
   left, right = 0, max(bloomDay) + 1
   while left < right:
      mid = (left + right)//2
      if possible(mid):
         right = mid
      else:
         left = mid + 1
   if possible(left):
      return left
   else:
      return left + 1
bloomDay = [5,5,5,5,10,5,5]
m = 2
k = 3
print(solve(bloomDay, m, k))

Input

[5,5,5,5,10,5,5], 2, 3

Output

10