Problem Statement 
 A quadratic equation has the format ax^2 + bx + c = 0 where a != 0.
To solve this equation the quadratic formula is used:
x = (b (+) sqrt(b^2  4ac)) / 2a ,
where (+) means plus or minus, sqrt means square root, and x is the solution.
Given a list of values for a, b and c your method will return a sorted int[] of
all integer solutions to the corresponding quadratic equations. The sorted values should be in
ascending order with no repeats. For example, if a = {1} ,
b = {2,3} ,
and c = {2,1} ,
your method would have to solve the quadratic equations corresponding to all combinations of values from a, b and c. This would amount to solving: x^2 + 2x + 2 = 0 (Solutions : not integers)
x^2 + 2x + 1 = 0 (Solutions : 1)
x^2 + 3x + 2 = 0 (Solutions : 2,1)
x^2 + 3x + 1 = 0 (Solutions : not integers) .
Notice that all combinations have been tried. The return value would be {2,1}.


Definition 
 Class:  QuadraticRoots  Method:  findRoots  Parameters:  int[], int[], int[]  Returns:  int[]  Method signature:  int[] findRoots(int[] a, int[] b, int[] c)  (be sure your method is public) 




Constraints 
  a, b, and c will each contain between 1 and 50 elements inclusive. 
  Each element of a will be nonzero, between 10000 and 10000 inclusive. 
  Each element of b and c will be between 10000 and 10000 inclusive. 
  The returned int[] will contain at most 100 elements. 

Examples 
0)  
 
1)  
 {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}  {1}  {1} 
 Returns: { }  

2)  
 {1}  {0}  {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16} 
 Returns: { 4, 3, 2, 1, 1, 2, 3, 4 }  

3)  
 {1,1,2,2,3,3,4,4}  {1,1,2,2,3,3,4,4}  {1,1,2,2,3,3,4,4} 
 Returns: { 3, 2, 1 }  

4)  
 {1,10000,10000}  {0,1,10000,10000}  {0,1,10000,10000} 
 Returns: { 10000, 100, 1, 0, 1, 100, 10000 }  
