Computer >> Computer tutorials >  >> Programming >> Python

Program to schedule tasks to take smallest amount of time in Python

Suppose we have a list of values called tasks where each different value represents a different task type, and we also have a non-negative integer k. Each task wants one minute to complete, but we must wait k minutes between doing two tasks of the same type. At any time, we can be doing a task or waiting. We have to find the smallest amount of time it takes to complete all the tasks.

So, if the input is like nums = [2, 2, 2, 3, 3, 2], k = 1, then the output will be 7, as the optimal ordering is [2, 3, 2, 3, 2, WAITING, 2].

To solve this, we will follow these steps −

  • c := count of all values in nums

  • ans := 0, lastsize := 0

  • while c is non−zero, do

    • lastsize := size of c

    • for each value x in most common (k + 1) values of c, do

      • c[x] := c[x] − 1

        • if c[x] is same as 0, then

          • remove c[x]

    • ans := ans + k + 1

  • return ans + lastsize - (k + 1)

Let us see the following implementation to get better understanding −

Example

class Solution:
   def solve(self, nums, k):
      from collections import Counter
      c = Counter(nums)
      ans = 0
      lastsize = 0
      while c:
         lastsize = len(c)
         for x, _ in c.most_common(k + 1):
            c[x] -= 1
            if c[x] == 0:
               del c[x]
         ans += k + 1
      return ans + lastsize - (k + 1)
ob1 = Solution()
nums = [2, 2, 2, 3, 3, 2]
k = 1
print(ob1.solve(nums, k))

Input

[2, 2, 2, 3, 3, 2], 1

Output

7