algoadvance

You are given an integer array nums. You need to return the average value of the even numbers that are divisible by three. If there are no such numbers, return 0.

Clarifying Questions

  1. Input Constraints:
    • What is the length of the input array?
    • What are the possible values in the input array?
    • Can the array contain negative numbers?
  2. Output Specifics:
    • Should the average be an integer or a float?

For the sake of this solution, I will assume:

Strategy

  1. Iterate through each number in the array.
  2. Check if the number is even and divisible by 3.
  3. Collect these numbers into a list.
  4. Calculate the average of the collected numbers.
  5. If the list is empty, return 0.
  6. Otherwise, return the average as a float.

Time Complexity

The algorithm consists of a single pass through the array to filter valid numbers and another step to compute the average. The time complexity is O(N), where N is the number of elements in the input array.

Code

def averageValueOfEvenNumbersDivisibleByThree(nums):
    # Filter even numbers that are also divisible by three
    valid_nums = [num for num in nums if num % 2 == 0 and num % 3 == 0]
    
    # If there are no valid numbers, return 0
    if not valid_nums:
        return 0.0
    
    # Calculate the average of the valid numbers
    average = sum(valid_nums) / len(valid_nums)
    return average

# Example usage:
nums = [1, 6, 9, 12, 15, 18]
print(averageValueOfEvenNumbersDivisibleByThree(nums))  # Output: 12.0

Explanation

  1. Filtering:
    • num % 2 == 0 ensures the number is even.
    • num % 3 == 0 ensures the even number is also divisible by 3.
  2. Computing the Average:
    • If valid_nums is empty, return 0.0.
    • Otherwise, compute the average using sum(valid_nums) / len(valid_nums) and return the result.

This approach ensures the solution is efficient and simple.

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