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  1. #1
    maz09 is offline Member
    Join Date
    Jan 2010
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    Default How to detect duplicate values in an Array?


    I need to find duplicate values in an array and get their indexes, by comparing every value with another.

    my code is below:

    Java Code:
    if array cotains: 0 1 1 0 1
    int[] array = new int[5];
    for(int i = 0; i<array.length(); i++{
      for(int j=1; j<array.length(); j++{
              //store index i and j
    the way i have searched the array doesn't compare every possibility. please help

  2. #2
    masijade is offline Senior Member
    Join Date
    Jun 2008
    Rep Power


    1. You need a closing paren on the if and for statements.
    2. length is a "property" not a method
    3. The outer loop need only go to array.length - 1 (there is no reason to compare the last index to any other index when all the other indexes have already been compared to it)
    4. Make the inner loop start a i + 1 rather than 1 (i.e. there is no reason to compare index 5 (outer) to index 1 (inner) when you've already compared index 1 (outer) to index 5 (inner)).

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