Check if Sequence Can Form Arithmetic Progression in Python

Suppose we have a list of numbers called nums. We have to check whether the elements present in nums are forming AP series or not. As we know in AP (Arithmetic Progression) series the common difference between any two consecutive elements is the same.

So, if the input is like nums = [9,1,17,5,13], then the output will be True because if we sort them, it will be [1,5,9,13,17] and here common difference is 4 for each pair of elements.

To solve this, we will follow these steps −

• nums := sort the list nums

• if number of elements in nums > 1, then

  • const := nums[1] - nums[0]

• otherwise,

  • return True

• for i in range 0 to size of nums -1, do

  • if nums[i+1] - nums[i] is not same as const, then

    • return False

• return True

Example (Python)

Let us see the following implementation to get better understanding −

 Live Demo

def solve(nums):
   nums = sorted(nums)

   if len(nums) > 1:
      const = nums[1] - nums[0]
   else:
      return True
   for i in range(len(nums)-1):
      if nums[i+1] - nums[i] != const:
         return False
   return True

nums = [9,1,17,5,13]
print(solve(nums))

Input

[9,1,17,5,13]

Output

True