Find Number of Sublists to Partition a List in Python

Suppose we have a list of numbers called nums. We can partition the list into some individual sublists then sort each piece. We have to find the maximum number of sublists we can partition to such that nums as a whole is sorted afterwards.

So, if the input is like nums = [4, 3, 2, 1, 7, 5], then the output will be 2, as we can sort the sublists like [4, 3, 2, 1] and [7, 5]

To solve this, we will follow these steps:

• count := 0
• main_sum := 0, sorted_sum := 0
• for each element x from nums and y from sorted form of nums, do
  • main_sum := main_sum + x
  • sorted_sum := sorted_sum + y
  • if main_sum is same as sorted_sum, then
    • count := count + 1
• return count

Let us see the following implementation to get better understanding:

Example

Live Demo

class Solution:
   def solve(self, nums):
      count = 0
      main_sum = sorted_sum = 0

      for x, y in zip(nums, sorted(nums)):
         main_sum += x
         sorted_sum += y
         if main_sum == sorted_sum:
            count += 1

      return count

ob = Solution()
nums = [4, 3, 2, 1, 7, 5]
print(ob.solve(nums))

Input

[4, 3, 2, 1, 7, 5]

Output

2