Reversing a singly linked list iteratively

Question

Has to be O(n) and in-place (space complexity of 1). The code below does work, but is there a simpler or better way?

public void invert() {
    if (this.getH         


        

Answer 1

public void invert() {  
  if (first == null) return;  
  Node prev = null;  
  for ( Node next = first.next; next != null; next = first.next) {  
    first.next = prev;  
    prev = first;  
    first = next;  
  }  
  first.next = prev;  
}