Average Value of Even Numbers That Are Divisible by Three

Problem Description

Given an integer array nums of positive integers, return the average value of all even integers that are divisible by 3. Note that the average of n elements is the sum of the n elements divided by n and rounded down to the nearest integer.

Key Insights

• We need to filter the array for even numbers first.
• Then, we check which of those even numbers are divisible by 3.
• Finally, we calculate the average of these filtered numbers, ensuring we round down.

Space and Time Complexity

Time Complexity: O(n) - We iterate through the list once to filter and sum the numbers. Space Complexity: O(1) - We use a constant amount of additional space for counters and sums.

Solution

To solve the problem, we will:

1. Initialize a sum variable to accumulate the values and a count variable to track how many valid numbers we find.
2. Iterate through each number in the array nums.
3. For each number, check if it is even (i.e., num % 2 == 0) and if it is divisible by 3 (i.e., num % 3 == 0).
4. If both conditions are met, add the number to the sum and increment the count.
5. After processing all numbers, if the count is greater than 0, compute the average by dividing the total sum by the count and rounding down. If no valid numbers were found, return 0.

Code Solutions