title: How to improve the code to return the unpaired element
body: <p>I am practising for an upcoming coding interview and here is one of my practice problems and my progress.</p>
  <p>How can I improve the program and what is your advice?</p>
  <p>Also, are there any cities that could help with improving my coding skills?</p>
  <p>Question:</p>
  <pre><code>    A non-empty zero-indexed array A consisting of N integers is given. The array contains an odd number of elements, and each element of the array can be paired with another element that has the same value, except for one element that is left unpaired.
      
      For example, in array A such that:
      
        A[0] = 9  A[1] = 3  A[2] = 9
        A[3] = 3  A[4] = 9  A[5] = 7
        A[6] = 9
      the elements at indexes 0 and 2 have value 9,
      the elements at indexes 1 and 3 have value 3,
      the elements at indexes 4 and 6 have value 9,
      the element at index 5 has value 7 and is unpaired.
      Write a function:
      
      class Solution { public int solution(int[] A); }
      
    that, given an array A consisting of N integers fulfilling the above conditions, returns the value of the unpaired element.
      
      For example, given array A such that:
      
        A[0] = 9  A[1] = 3  A[2] = 9
        A[3] = 3  A[4] = 9  A[5] = 7
        A[6] = 9
      the function should return 7, as explained in the example above.
      
      Assume that:
      
      N is an odd integer within the range [1..1,000,000];
      each element of array A is an integer within the range [1..1,000,000,000];
      all but one of the values in A occur an even number of times.
      Complexity:
      
      expected worst-case time complexity is O(N);
      expected worst-case space complexity is O(1), beyond input storage (not counting the storage required for input arguments).
      Elements of input arrays can be modified.
  </code></pre>
  <p>Solution:</p>
  <pre><code>import java.util.*;
  
  public class Solution {
      public int solution(int[] A) {
              int x;
  
          for(int i = 0; i &lt; 7; i++)
          {
               //create an integer array containing an odd number of elements of numbers ranging from 1 - 1,000,000
              
  //for(int N = 1; N &lt;= 1,000,000; N++)
  
              int N = 1;
  
              while(N &gt; 1 &amp;&amp; N &lt;= 1000000)
              {
  
                  //check if N is odd then assign to the array               
  
                  if(N != N/2)
                  {
                      A[i] = N;
                  }
              }
  
              //check for any element not paired more than once
  
              if(A[i] != A[i++])
              {
                  x = A[i];
              }
              else 
                  return 0;
          }
  
          //return unpaired elemnent
          return x;
      }
  }
  </code></pre>