title: Algorithm to find odd item (with no pairs) in an array?
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/35185/finding-a-single-number-in-a-list">Finding a single number in a list</a>  </p>
  </blockquote>
  
  
  
  <p>What to be a good algorithm given an array of integers, all but one of which appears an even number of times, find the one integer which appears an odd number of times.</p>
  
  <p>Perhaps something along the lines of binary search like sum all elements of 2 small arrays of  n/2 size, compare recursively find out?</p>
  
  <p>Edit:</p>
  
  <p>Is this XOR algorithm actually assuming {1,1,4,4,7,7,5,8,8,9,9}? My input can be randmon too - { 1,4,1,8,9,5,4,5,9,8}. So the logic changes in that case? </p>