Merge pull request gzc426#376 from coolbhy/patch-7

gzc426 · web-flow · commit 39b11b21f572 · 2018-12-08T11:42:13.000+08:00
Create 啦啦啦.md
diff --git a/2018.12.07-leetcode104/啦啦啦.md b/2018.12.07-leetcode104/啦啦啦.md
@@ -0,0 +1,40 @@
+```java
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public int maxDepth(TreeNode root) {
+        if(root==null)return 0;
+        Queue<TreeNode> q = new LinkedList<>();
+        q.add(root);
+        int level = 0;
+        int next=0;
+        int last=1;
+        while(!q.isEmpty()){
+            TreeNode r = q.poll();
+            last--;
+            if(r.left!=null){
+                q.add(r.left);
+                next++;
+            }
+            if(r.right!=null){
+                q.add(r.right);
+                next++;
+            }
+            
+            if(last==0){
+                level++;
+                last=next;
+                next=0;
+            }
+        }
+        return level;
+    }
+}
+```
