Runtime cost of dynamic type resolution in C Sharp (C#) - Time & Space Complexity

Time Complexity: Runtime cost of dynamic type resolution

O(n)

Understanding Time Complexity

When a program uses dynamic types, it decides the exact type while running, not before. This can affect how long the program takes to run.

We want to know how this decision-making time grows as the program runs more dynamic operations.

Scenario Under Consideration

Analyze the time complexity of the following code snippet.

    dynamic value = GetDynamicValue();
    for (int i = 0; i < n; i++)
    {
        // Each call resolves the method at runtime
        var result = value.Compute(i);
    }
    

This code calls a method on a dynamic object inside a loop, resolving the method type each time.

Identify Repeating Operations

Identify the loops, recursion, array traversals that repeat.

• Primary operation: Calling a method on a dynamic object, which requires runtime type resolution.
• How many times: This happens once per loop iteration, so n times.

How Execution Grows With Input

Each loop iteration does a runtime check to find the right method to call. As n grows, these checks add up linearly.

Input Size (n)	Approx. Operations
10	About 10 dynamic resolutions
100	About 100 dynamic resolutions
1000	About 1000 dynamic resolutions

Pattern observation: The total work grows directly with the number of loop runs.

Final Time Complexity

Time Complexity: O(n)

This means the time to run grows in a straight line as the number of dynamic calls increases.

Common Mistake

[X] Wrong: "Dynamic calls are free or constant time like normal calls."

[OK] Correct: Each dynamic call needs extra work to find the right method at runtime, so it costs more than a normal call and adds up with more calls.

Interview Connect

Understanding how dynamic typing affects runtime helps you write clearer, more efficient code and shows you can think about how programs behave under the hood.

Self-Check

What if the dynamic object's type was cached after the first call? How would that change the time complexity?