Computed properties in C Sharp (C#) - Time & Space Complexity

Time Complexity: Computed properties

O(n)

Understanding Time Complexity

Let's see how the time it takes to get a computed property changes as the data grows.

We want to know how the cost of calculating a property depends on the size of the input.

Scenario Under Consideration

Analyze the time complexity of the following code snippet.

public class Numbers
{
    public int[] Values { get; set; }

    public int Sum => Values.Sum();
}

This code defines a computed property Sum that calculates the total of all numbers in an array.

Identify Repeating Operations

Identify the loops, recursion, array traversals that repeat.

• Primary operation: Summing all elements in the array inside the computed property.
• How many times: Once each time the Sum property is accessed, it loops through all elements.

How Execution Grows With Input

When the array has more numbers, the sum takes longer because it adds each number one by one.

Input Size (n)	Approx. Operations
10	10 additions
100	100 additions
1000	1000 additions

Pattern observation: The work grows directly with the number of items; double the items, double the work.

Final Time Complexity

Time Complexity: O(n)

This means the time to get the computed sum grows in a straight line with the number of elements.

Common Mistake

[X] Wrong: "Accessing the computed property is instant no matter the array size."

[OK] Correct: Each time you ask for the sum, the program adds up all numbers again, so bigger arrays take more time.

Interview Connect

Understanding how computed properties work helps you explain performance in real code and shows you think about efficiency clearly.

Self-Check

"What if we stored the sum once and updated it only when the array changes? How would the time complexity change when accessing the sum?"