Using JAVA, Find all numbers z such that both z and z2 are in the sequence, or report that no such number exists. Describe the fastest algorithm you can think of for this problem and give its running...

Using JAVA, Find all numbers z such that both z and z2 are in the sequence, or report that no such number exists. Describe the fastest algorithm you can think of for this problem and give its running time complexity. Also clearly describe the data structures you use.