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Data Structure

Algorithm Analysis - I

  1. The TimerUtil class
    • This class contains a single method (measureTime) whose job is:
    • Start a timer
    • Run the code you want to measure
    • Stop the timer
    • Return the time taken
    • Think of it like a stopwatch:
    • You give it some code -> it tells you how long it took. 
      class TimerUtil {
    // This method accepts any code block using Runnable
    public static long measureTime(Runnable task) {
        long start = System.nanoTime();
        task.run();
        long end = System.nanoTime();
        return end - start;
    }
}
  2. The main program 
    class CheckRunTime{
    public static void main(String[] args) {
        long duration = TimerUtil.measureTime(() -> {
            long sum = 0;
            for (long i = 1; i < 9000000; i++) {
                sum += i;
            }
            System.out.println("Sum = " + sum);
        });
        System.out.println("Time (ns): " + duration);
        System.out.println("Time (ms): " + duration / 1_000_000.0);  
    }
}
    • In the main class, we call the TimerUtil.measureTime(...) method and give it the algorithm we want to test.
    • In this example, the algorithm is just adding numbers from 1 to 9000000.
    • The timer measures how long that loop takes and gives the duration back.
    • Then we print the result in nanoseconds and milliseconds.
  3. Why this is useful?
    • You can test any algorithm (sorting, searching, loops, etc.) using the same timing method.
    • The main program stays clean and easy to read.
    • You won't repeat timing code everywhere - just reuse measureTime().