code prefext

.idea/misc.xml

@@ -35,7 +35,7 @@
       </value>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" project-jdk-name="1.8" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
   <component name="ProjectType">

testlib/src/main/java/temp/Test20190805_ListNode.java

 package temp;
 
+import java.util.List;
+
 /**
  * Description: <Test20190805_ListNode><br>
- * Author:      mxdl<br>
- * Date:        2019/8/5<br>
- * Version:     V1.0.0<br>
- * Update:     <br>
+ * Author: mxdl<br>
+ * Date: 2019/8/5<br>
+ * Version: V1.0.0<br>
+ * Update: <br>
  */
 public class Test20190805_ListNode {
+  // 1.判断链表有没有环
+  public static boolean isListNodeRing(ListNode listNode) {
+    ListNode slowNode = listNode;
+    ListNode fastNode = listNode;
+    while (fastNode.next != null) {
+      slowNode = slowNode.next;
+      fastNode = fastNode.next.next;
+      if (slowNode == fastNode) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // 2.判断链表有没有环，有环则找到链表的入口节点
+  public static ListNode getRinigEntry(ListNode listNode) {
+    ListNode slowNode = listNode;
+    ListNode fastNode = listNode;
+    boolean isring = false;
+    while (fastNode.next != null) {
+      slowNode = slowNode.next;
+      fastNode = fastNode.next.next;
+      if (slowNode == fastNode) {
+        isring = true;
+        break;
+      }
+    }
+    if (!isring) {
+      return null;
+    }
+    fastNode = listNode;
+    while (slowNode != fastNode) {
+      slowNode = slowNode.next;
+      fastNode = fastNode.next;
+    }
+    return fastNode;
+  }
+
+  // 3.翻转一个链表
+  public static ListNode reversListNode(ListNode listNode) {
+    ListNode reversNode = null;
+    ListNode currNode = listNode;
+    ListNode preNdoe = null;
+    while (currNode != null) {
+      ListNode nextNode = currNode.next;
+      if (nextNode == null) {
+        reversNode = currNode;
+      }
+      currNode.next = preNdoe;
+      preNdoe = currNode;
+      currNode = nextNode;
+    }
+    return reversNode;
+  }
+
+  // 4.删除链表的倒数第n个节点
+  public static ListNode deleteListNode(ListNode listNode, int n) {
+    ListNode pa = listNode;
+    ListNode pb = listNode;
+    int i = 1;
+    while (i <= n) {
+      pa = pa.next;
+      i++;
+    }
+    while (pa.next != null) {
+      pa = pa.next;
+      pb = pb.next;
+    }
+    pb.next = pb.next.next;
+    return listNode;
+  }
+
+  // 5.合并两个有序链表
+  public static ListNode mergeListNode(ListNode pa, ListNode pb) {
+    ListNode listNode = new ListNode(0);
+    ListNode currNode = listNode;
+    while (pa != null && pb != null) {
+      if (pa.val > pb.val) {
+        currNode.next = pb;
+        pb = pb.next;
+      } else {
+        currNode.next = pa;
+        pa = pa.next;
+      }
+      currNode = currNode.next;
+    }
+    currNode.next = pa != null ? pa : pb;
+    return listNode.next;
+  }
+
+  public static void main(String[] args) {
+    ListNode listNode = new ListNode(1);
+    ListNode listNode1 = new ListNode(3);
+    ListNode listNod2 = new ListNode(5);
+
+    ListNode listNode3 = new ListNode(2);
+    ListNode listNode4 = new ListNode(4);
+    ListNode listNode5 = new ListNode(6);
+    listNode.next = listNode1;
+    listNode1.next = listNod2;
+
+    listNode3.next = listNode4;
+    listNode4.next = listNode5;
+    // listNode4.next = listNode3;
+    // boolean isRing = isListNodeRing(listNode);
+    // System.out.println("isRing:"+isRing);
+
+    // ListNode rinigEntry = getRinigEntry(listNode);
+    // System.out.println("entry:"+(rinigEntry != null ? rinigEntry.val:" is null"));
+
+    // ListNode reversNode = reversListNode(listNode);
+    // while(reversNode != null){
+    // System.out.println("val:"+reversNode.val);
+    // reversNode = reversNode.next;
+    // }
+    ListNode reversNode = mergeListNode(listNode, listNode3);
+    while (reversNode != null) {
+      System.out.println("val:" + reversNode.val);
+      reversNode = reversNode.next;
+    }
+
+  }
 }