Merge pull request gzc426#22 from beddingearly/beddingearly-patch-13

beddingearly · web-flow · commit 83b307917bb2 · 2018-12-05T16:24:55.000+08:00
Create Tony the Cyclist.md
diff --git a/2018.12.05-leetcode102/Tony the Cyclist.md b/2018.12.05-leetcode102/Tony the Cyclist.md
@@ -0,0 +1,50 @@
+```java
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+import java.util.*;
+class Solution {
+    public List<List<Integer>> levelOrder(TreeNode root) {
+        if (root == null){
+            return new ArrayList<>();
+        }
+        List<List<Integer>> list = new ArrayList<>();
+        List<Integer> tmp = new ArrayList<>();
+        ArrayDeque<TreeNode> d = new ArrayDeque<>();
+        tmp.add(root.val);
+        list.add(new ArrayList<>(tmp));
+        tmp.clear();
+        if (root.left != null){
+            d.addFirst(root.left);
+        }
+        if (root.right != null){
+            d.addFirst(root.right);
+        }
+        int level = d.size();
+        while (!d.isEmpty()){
+            TreeNode node = d.pollLast();
+            tmp.add(node.val);
+            level--;
+            if (node.left != null){
+                d.addFirst(node.left);
+            }
+            if (node.right != null){
+                d.addFirst(node.right);
+            }
+            if (level == 0){
+                if (!tmp.isEmpty())
+                    list.add(new ArrayList<>(tmp));
+                level = d.size();
+                tmp.clear();
+            }
+        }
+        return list;
+    }
+}
+```
