Rotate List

Author: mengli

RotateList.java

@@ -0,0 +1,36 @@
+/**
+ * Given a list, rotate the list to the right by k places, where k is
+ * non-negative.
+ * 
+ * For example:
+ * 
+ * Given 1->2->3->4->5->NULL and k = 2, return 4->5->1->2->3->NULL.
+ * 
+ */
+
+public class RotateList {
+	public ListNode rotateRight(ListNode head, int n) {
+		if (head == null)
+			return head;
+		int length = 1;
+		ListNode last = head;
+		while (last.next != null) {
+			last = last.next;
+			length++;
+		}
+		n = n % length;
+		if (n == 0)
+			return head;
+		int steps = length - n;
+		ListNode start = new ListNode(0);
+		start.next = head;
+		while (steps > 0) {
+			start = start.next;
+			steps--;
+		}
+		ListNode ret = start.next;
+		start.next = null;
+		last.next = head;
+		return ret;
+	}
+}