Alarm acknowledgment workflow in SCADA systems - Time & Space Complexity

Time Complexity: Alarm acknowledgment workflow

O(n)

Understanding Time Complexity

We want to understand how the time to acknowledge alarms grows as the number of alarms increases in a SCADA system.

How does the system handle more alarms without slowing down too much?

Scenario Under Consideration

Analyze the time complexity of the following alarm acknowledgment workflow.

function acknowledgeAlarms(alarmList) {
  for (let i = 0; i < alarmList.length; i++) {
    if (alarmList[i].status == 'active') {
      alarmList[i].status = 'acknowledged';
      logAcknowledgment(alarmList[i]);
    }
  }
}

This code loops through all alarms and acknowledges each active alarm by changing its status and logging it.

Identify Repeating Operations

Look for repeated actions in the code.

• Primary operation: Looping through each alarm in the alarm list.
• How many times: Once for every alarm in the list.

How Execution Grows With Input

As the number of alarms increases, the time to process grows proportionally.

Input Size (n)	Approx. Operations
10	About 10 checks and possible acknowledgments
100	About 100 checks and possible acknowledgments
1000	About 1000 checks and possible acknowledgments

Pattern observation: The work grows evenly as the number of alarms grows.

Final Time Complexity

Time Complexity: O(n)

This means the time to acknowledge alarms grows directly with the number of alarms.

Common Mistake

[X] Wrong: "Acknowledging alarms happens instantly no matter how many alarms there are."

[OK] Correct: Each alarm must be checked and updated, so more alarms mean more work and more time.

Interview Connect

Understanding how processes scale with input size is a key skill. It shows you can predict system behavior as it grows.

Self-Check

"What if the system only acknowledged alarms that met a certain priority? How would that change the time complexity?"