33import me .premaseem .myLib .MyDLLNode ;
44import org .junit .Test ;
55
6+ /**
7+ ### Return Kth to Last:
8+ Implement an algorithm to find the kth to last element of a singly linked list.
9+
10+ */
611public class ReturnKToLast {
712
813 // Test Driven Development by Aseem Jain
@@ -24,33 +29,31 @@ private MyDLLNode solution1(MyDLLNode head, int k) {
2429 // count total number in one loop.
2530 // iterate for last - k to return element
2631 MyDLLNode c = head ;
27- int len =0 ;
28- while (c != null ){
32+ int len =0 ;
33+ while (c != null ){
2934 len ++;
3035 c = c .next ;
3136 }
3237
33- c = head ;
34- for (int i = 1 ; i <= len -k ; i ++, c = c .next ) {
38+ System .out .println ("the total leng is " + len );
3539
40+ c = head ;
41+ for (int i = 1 ; i <= len -k ; i ++) {
42+ c = c .next ;
3643 }
3744 return c ;
3845 }
3946
4047 private MyDLLNode solution2 (MyDLLNode head , int k ) {
41- 42- // count total number in one loop.
43- // iterate for last - k to return element
4448 MyDLLNode c = head ;
45- while (c .next != null ){
49+ while (c .next != null ){
4650 c = c .next ;
4751 }
4852
49- MyDLLNode last = c ;
50- 51- for (int i = 1 ; i < k ; i ++, last = last .prev ) {
52- 53+ for (int i = 1 ; i < k ; i ++) {
54+ c = c .prev ;
5355 }
54- return last ;
56+ 57+ return c ;
5558 }
5659}
0 commit comments