If-else expression assignment in Kotlin - Time & Space Complexity

Time Complexity: If-else expression assignment

O(1)

Understanding Time Complexity

Let's see how the time it takes to run code changes when we use an if-else expression to assign a value.

We want to know how the program's steps grow as input changes.

Scenario Under Consideration

Analyze the time complexity of the following code snippet.

val number = 10
val result = if (number % 2 == 0) {
    "Even"
} else {
    "Odd"
}
println(result)
    

This code checks if a number is even or odd and assigns a string based on that.

Identify Repeating Operations

Identify the loops, recursion, array traversals that repeat.

• Primary operation: A single if-else check.
• How many times: Exactly once per run.

How Execution Grows With Input

The program does the same steps no matter what number you use.

Input Size (n)	Approx. Operations
10	1 check
100	1 check
1000	1 check

Pattern observation: The number of steps stays the same even if the input changes.

Final Time Complexity

Time Complexity: O(1)

This means the program takes the same amount of time no matter the input size.

Common Mistake

[X] Wrong: "If-else checks take longer as the number gets bigger."

[OK] Correct: The check only looks at the number once, so size doesn't affect time.

Interview Connect

Understanding simple if-else assignments helps you explain how decisions in code affect speed, a key skill in many coding tasks.

Self-Check

"What if we replaced the if-else with a loop that checks every number up to 'number'? How would the time complexity change?"