Dynamic typing vs strong typing in Ruby - Performance Comparison

Time Complexity: Dynamic typing vs strong typing

O(1)

Understanding Time Complexity

When we talk about dynamic typing and strong typing in Ruby, we want to understand how these features affect the speed of running programs.

Specifically, we ask: How does Ruby's way of handling types impact the time it takes to run code?

Scenario Under Consideration

Analyze the time complexity of the following Ruby code that uses dynamic and strong typing.

    def add_values(a, b)
      if a.is_a?(Integer) && b.is_a?(Integer)
        a + b
      else
        "Cannot add non-integers"
      end
    end

    result = add_values(5, 10)
    puts result
    

This code checks the types of inputs at runtime and adds them if both are integers.

Identify Repeating Operations

Look for operations that repeat or take time as input grows.

• Primary operation: Type checking with is_a? method calls.
• How many times: Twice per function call, once for each input.

How Execution Grows With Input

The time to check types stays the same no matter how big the numbers are because it only looks at the type, not the value size.

Input Size (n)	Approx. Operations
10	2 type checks + 1 addition
100	2 type checks + 1 addition
1000	2 type checks + 1 addition

Pattern observation: The number of operations does not grow with input size; it stays constant.

Final Time Complexity

Time Complexity: O(1)

This means the time to run this code stays the same no matter how big the input numbers are.

Common Mistake

[X] Wrong: "Checking types slows down the program a lot as inputs get bigger."

[OK] Correct: Type checks look only at the kind of data, not its size, so they take the same time regardless of input size.

Interview Connect

Understanding how dynamic and strong typing affect program speed helps you explain how Ruby handles data behind the scenes, a useful skill for writing clear and efficient code.

Self-Check

"What if we changed the type checks to happen inside a loop over a list of inputs? How would the time complexity change?"