Continue statement in Java - Time & Space Complexity

Time Complexity: Continue statement

O(n)

Understanding Time Complexity

Let's see how using the continue statement affects the time complexity of a loop.

We want to know how the number of steps changes as the 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;
    }
    System.out.println(i);
}
    

This code loops from 0 to n-1, skips even numbers using continue, and prints only odd numbers.

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: The loop runs n times, but the print happens only for about half of them.

How Execution Grows With Input

As n grows, the loop runs more times, but continue skips some steps.

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

Pattern observation: The loop runs n times, but the print runs about n/2 times. The continue skips printing for half the cases.

Final Time Complexity

Time Complexity: O(n)

This means the total steps grow linearly with the input size, even with continue skipping some steps.

Common Mistake

[X] Wrong: "Using continue makes the loop run faster and reduces time complexity."

[OK] Correct: Continue only skips some steps inside the loop but the loop still runs n times, so the overall time grows linearly with n.

Interview Connect

Understanding how continue affects loops helps you explain code behavior clearly and shows you can analyze performance carefully.

Self-Check

"What if we replaced continue with a nested if statement that only prints when i is odd? How would the time complexity change?"

Practice

1. What does the continue statement do inside a loop in Java?

easy

A. Skips the rest of the current loop iteration and moves to the next iteration

B. Stops the entire loop immediately

C. Exits the current method

D. Restarts the program from the beginning

Solution

1. Step 1: Understand the role of continue

   The continue statement skips the remaining code in the current loop iteration.

2. Step 2: Effect on loop execution

   After skipping, the loop moves to the next iteration without stopping the entire loop.

3. Final Answer:

   Skips the rest of the current loop iteration and moves to the next iteration -> Option A

4. Quick Check:

   continue skips current step [OK]

Hint: Continue skips current loop step, not whole loop [OK]

Common Mistakes:

• Confusing continue with break
• Thinking continue exits the method
• Assuming continue restarts the program

2. Which of the following is the correct syntax to use continue inside a for loop in Java?

easy

A. continue;

B. continue()

C. continue loop;

D. continue[];

Solution

1. Step 1: Recall Java continue syntax

   The continue statement is used alone followed by a semicolon inside loops.

2. Step 2: Check each option

   continue; uses correct syntax: continue;. Others are invalid syntax in Java.

3. Final Answer:

   continue; -> Option A

4. Quick Check:

   Correct continue syntax ends with semicolon [OK]

Hint: Use just 'continue;' with semicolon inside loops [OK]

Common Mistakes:

• Adding parentheses after continue
• Using labels without proper syntax
• Adding brackets or other symbols

3. What is the output of this Java code?

for (int i = 1; i <= 5; i++) {
  if (i == 3) continue;
  System.out.print(i + " ");
}

medium

A. 1 2 3 4 5

B. 1 2 4 5

C. 1 2 3 4

D. 2 3 4 5

Solution

1. Step 1: Analyze loop iterations

   The loop runs i from 1 to 5. When i equals 3, the continue skips printing.

2. Step 2: Determine printed values

   Values printed are 1, 2, 4, 5 with spaces after each.

3. Final Answer:

   1 2 4 5 -> Option B

4. Quick Check:

   Skip i=3, print others [OK]

Hint: Continue skips printing 3, so output excludes 3 [OK]

Common Mistakes:

• Including 3 in output
• Stopping loop at 3
• Printing without spaces

4. Identify the error in this code snippet:

for (int i = 0; i < 5; i++) {
  if (i == 2)
    continue
  System.out.println(i);
}

medium

A. System.out.println should be before continue

B. continue cannot be used inside for loops

C. Missing semicolon after continue statement

D. Loop condition is incorrect

Solution

1. Step 1: Check syntax of continue

   The continue statement must end with a semicolon in Java.

2. Step 2: Identify missing semicolon

   Code misses semicolon after continue, causing syntax error.

3. Final Answer:

   Missing semicolon after continue statement -> Option C

4. Quick Check:

   continue requires semicolon [OK]

Hint: Always put semicolon after continue [OK]

Common Mistakes:

• Omitting semicolon after continue
• Thinking continue can't be in for loops
• Misplacing print statement

5. How can you use continue to print only odd numbers from 1 to 10 in Java?

hard

A. Use continue outside the loop

B. Use continue when number is odd to skip printing

C. Use break when number is even to stop loop

D. Use continue when number is even to skip printing

Solution

1. Step 1: Identify condition to skip even numbers

   To print only odd numbers, skip even numbers using continue.

2. Step 2: Apply continue inside loop

   When number is even, continue skips printing and moves to next iteration.

3. Final Answer:

   Use continue when number is even to skip printing -> Option D

4. Quick Check:

   Skip even numbers with continue [OK]

Hint: Skip even numbers with continue to print odds [OK]

Common Mistakes:

• Skipping odd numbers instead of even
• Using break instead of continue
• Placing continue outside loop