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Thread: Whats the big-o notation (running time) of the following in java?

  1. #1
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    Default Whats the big-o notation (running time) of the following in java?

    Hi, I am doing some study for an upcoming exam, I was wondering if anyone could help me figure out the running time of these arrays/ methods in java? Also if anyone has any good resources for studying data structures and algorithms I would be very grateful.

    Can anyone tell me the running time of the following parts of the class definition?

    The array declaration AND initialization shown at ‘A’. b) The method isSet() shown at ‘B' c) The method contains() shown at ‘C’. d) The method sort() shown at ‘D’.

    Thanks in advance!!

    CODE:

    `````````````````````````````````````````````````` `````````````````````````

    package ie.gmit;

    import java.util.Arrays;

    public class Numbers {
    private int[] numbers = {87,32,29,13,6,45,32,17}; //<-----A

    public boolean isSet() { //<----B
    for (int i = 0; i < numbers.length; i++) {
    for (int j =0; j < numbers.length; j++) {
    if (i != j && numbers[i] == numbers[j])
    return false;

    }
    }
    return true;
    }

    public boolean contains (int num) { // <------ C
    return Arrays.binarySearch(numbers, num)> -1;

    }

    public void sort() { //<------D
    Arrays.sort(numbers);
    }

    }


    `````````````````````````````````````````````````` `````````````````````````

  2. #2
    Member MrLowBot's Avatar
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    Default Re: Whats the big-o notation (running time) of the following in java?

    import java.util.Arrays;
     
    public class Numbers {
     
    	public static void main(String[] args) {
     
    		System.out.println(isSet());
    		System.out.println(contains(6));
    		sort();
     
    	}
     
    	private static int[] numbers = { 87, 32, 29, 13, 6, 45, 32, 17 }; // <-----A
     
    	public static boolean isSet() { // <----B
    		for (int i = 0; i < numbers.length; i++) {
    			for (int j = 0; j < numbers.length; j++) {
    				if (i != j && numbers[i] == numbers[j])
    					return false;
     
    			}
    		}
    		return true;
    	}
     
    	public static boolean contains(int num) { // <------ C
    		return Arrays.binarySearch(numbers, num) > -1;
     
    	}
     
    	public static void sort() { // <------D
    		Arrays.sort(numbers);
    		for (int k : numbers) {
    			System.out.print(k + " ");
    		}
    	}
     
    }


    Can't tell you the run time but i thought that i would just add somethings.
    "Tick, tack"

  3. #3
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    Default Re: Whats the big-o notation (running time) of the following in java?

    <<Easy Learning Data Structures & Algorithms Java Practice >> good for you

    en.verejava.com

    package com.tool.util;
     
    import java.util.Arrays;
     
    public class Numbers {
     
        private int[] numbers = { 87, 32, 29, 13, 6, 45, 32, 17 }; 
     
        public boolean isSet() { 
            for (int i = 0; i < numbers.length; i++) {
                for (int j = 0; j < numbers.length; j++) {
                    if (i != j && numbers[i] == numbers[j])
                        return false;
                }
            }
            return true;
        }
     
        public boolean contains(int num) { 
            return Arrays.binarySearch(numbers, num) > -1;
        }
     
        public void sort() { 
            Arrays.sort(numbers);
        }
     
        public void print()
        {
            for(int i=0;i<numbers.length;i++)
            {
                System.out.print(numbers[i]+", ");
            }
        }
     
        public static void main(String[] args) {
     
            Numbers numbers=new Numbers();
            numbers.sort();
            numbers.print();
     
        }
     
    }

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