Continue statement in C++ - Time & Space Complexity

Time Complexity: Continue statement

O(n)

Understanding Time Complexity

We want to see how using the continue statement affects how long a program takes to run.

Specifically, does skipping some steps change the overall work done as input grows?

Scenario Under Consideration

Analyze the time complexity of the following code snippet.

for (int i = 0; i < n; i++) {
    if (i % 2 == 0) {
        continue;
    }
    // Some constant time work here
    int x = i * 2;
}
    

This code loops through numbers from 0 to n-1, skipping even numbers using continue.

Identify Repeating Operations

Identify the loops, recursion, array traversals that repeat.

• Primary operation: The for-loop runs from 0 to n-1.
• How many times: It runs n times, but the work inside after continue runs only for odd i values.

How Execution Grows With Input

As n grows, the loop runs n times, but the work after continue happens only about half the time.

Input Size (n)	Approx. Operations
10	10 loop checks, 5 work executions
100	100 loop checks, 50 work executions
1000	1000 loop checks, 500 work executions

Pattern observation: The total loop runs grow linearly with n, and the work inside grows roughly half as fast.

Final Time Complexity

Time Complexity: O(n)

This means the program's running time grows in a straight line as the input size increases, even with the continue skipping some steps.

Common Mistake

[X] Wrong: "Using continue makes the loop run faster and changes the time complexity to less than linear."

[OK] Correct: The loop still runs n times; skipping some steps only reduces work by a constant factor, not the overall growth pattern.

Interview Connect

Understanding how control statements like continue affect time helps you explain your code clearly and reason about efficiency in real projects.

Self-Check

"What if the continue condition depended on a nested loop? How would that change the time complexity?"