lintcode 中的第 102 题，检查一个链表中是否带环

src/test/java/com/ossez/lang/tutorial/tests/lintcode/LintCode0102HasCycleTest.java

@@ -0,0 +1,64 @@
+package com.ossez.lang.tutorial.tests.lintcode;
+
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.ossez.lang.tutorial.models.ListNode;
+
+/**
+ * <p>
+ * 1480
+ * <ul>
+ * <li>@see
+ * <a href= "https://www.cwiki.us/display/ITCLASSIFICATION/Dot+Product">https://www.cwiki.us/display/ITCLASSIFICATION/Dot+Product</a>
+ * <li>@see<a href= "https://www.lintcode.com/problem/dot-product/">https://www.lintcode.com/problem/dot-product/</a>
+ * </ul>
+ * </p>
+ * 
+ * @author YuCheng
+ *
+ */
+public class LintCode0102HasCycleTest {
+
+	private final static Logger logger = LoggerFactory.getLogger(LintCode0102HasCycleTest.class);
+
+	/**
+	 * 
+	 */
+	@Test
+	public void testMain() {
+		logger.debug("BEGIN");
+		// INIT LINKED LIST
+		ListNode head = new ListNode(1);
+		head.next = new ListNode(2);
+		head.next.next = new ListNode(3);
+		head.next.next.next = new ListNode(4);
+
+		// CREATE A LOOP
+		head.next.next.next.next = head.next.next.next;
+
+		boolean retResult = false;
+
+		// LIKED LIST MAY NULL:
+		if (!(head == null || head.next == null)) {
+			ListNode s = head;
+			ListNode f = head.next;
+
+			while (f.next != null && f.next.next != null) {
+
+				s = s.next;
+				f = f.next.next;
+
+				if (f == s) {
+					retResult = true;
+					break;
+				}
+			}
+		}
+
+		System.out.println(retResult);
+
+	}
+
+}