Finds the intersection of two arrays in a simple fashion.

gistfile1.js

/**
 * finds the intersection of
 * two arrays in a simple fashion.
 *
 * PARAMS
 *  @param a - first array, must already be sorted
 *  @param b - second array, must already be sorted
 *
 * NOTES
 *
 *  Should have O(n) operations, where n is
 *    n = MIN(a.length(), b.length())
 */
function intersect_safe(a, b)
{
  var ai=0, bi=0;
  var result = new Array();

  while( ai < a.length && bi < b.length )
  {
     if      (a[ai] < b[bi] ){ ai++; }
     else if (a[ai] > b[bi] ){ bi++; }
     else /* they're equal */
     {
       result.push(a[ai]);
       ai++;
       bi++;
     }
  }

  return result;
}