title: Calculating number of intersecting discs
body: <p>Please see this question and the accepted answer:</p>
  
  <p><a href="https://stackoverflow.com/questions/4801242/algorithm-to-calculate-number-of-intersecting-discs">Algorithm to calculate number of intersecting discs</a></p>
  
  <p>Instead of using a binary tree, what if you were to use an array, sort it and then simply iterate up through the array? Would it still be O(n log n)? </p>
  
  <p>Iterating through the sorted array (to me) seems like it would be O(n^2)....</p>