add 94

Author: awesomelike

medium/94-inorder-traversal.java

@@ -0,0 +1,34 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode() {}
+ *     TreeNode(int val) { this.val = val; }
+ *     TreeNode(int val, TreeNode left, TreeNode right) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+class Solution {
+  void inorder(TreeNode root, List<Integer> answer) {
+    if (root.left != null) {
+      inorder(root.left, answer);  
+    }
+    
+    answer.add(root.val);
+    
+    if (root.right != null) {
+      inorder(root.right, answer);  
+    }
+  }
+  public List<Integer> inorderTraversal(TreeNode root) {
+    List<Integer> answer = new LinkedList();  
+    if (root == null) return answer;
+    inorder(root, answer);
+    return answer;
+  }
+}