作业

xiaoxucong · xiaoxucong · commit 45f0078c94bc · 2020-06-21T17:54:18.000+08:00
diff --git a/Week02/N_tree_sequence.java b/Week02/N_tree_sequence.java
@@ -0,0 +1,43 @@
+package com.algorithm.ok.week_2;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+/***
+ * 429. N叉树的层序遍历
+ */
+public class N_tree_sequence {
+    @Test
+    public  void main() {
+
+    }
+
+    public List<List<Integer>> levelOrder(Node root) {
+        List<Node> children = new ArrayList<>();
+        List<List<Integer>> li = new ArrayList<>();
+        if(root == null) {
+            return li;
+        }
+        children.add(root);
+        test(children,li);
+        return li;
+    }
+
+    private void test(List<Node> children,List<List<Integer>> li) {
+        List<Integer> list = new ArrayList<>();
+        List<Node> childrenNode = new ArrayList<>();
+        if(children != null && children.size() > 0) {
+            for(int i= 0;i < children.size();i++){
+                list.add(children.get(i).val);
+                childrenNode.addAll(children.get(i).children);
+            }
+            li.add(list);
+            test(childrenNode,li);
+        }
+
+    }
+}
diff --git a/Week02/Two_tree_front.java b/Week02/Two_tree_front.java
@@ -0,0 +1,38 @@
+package com.algorithm.ok.week_2;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+/***
+ * 144. 二叉树的前序遍历
+ */
+public class Two_tree_front {
+    @Test
+    public  void main() {
+
+    }
+
+    //递归遍历
+    public List<Integer> preorderTraversal(TreeNode root) {
+        List<Integer> li = new ArrayList<>();
+        if(root == null) {
+            return li;
+        }
+        test(li,root);
+        return li;
+    }
+
+    private void  test(List<Integer> li,TreeNode root) {
+        li.add(root.val);
+        if(root.left != null){
+            test(li,root.left);
+        }
+        if(root.right != null){
+            test(li,root.right);
+        }
+    }
+}
