Create 671_12

Week_02/id_12/671_12

@@ -0,0 +1,31 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public int findSecondMinimumValue(TreeNode root) {
+        return traversal(root,root.val);
+    }
+
+    private int traversal(TreeNode root,int value){
+        if(root == null){
+            return -1;
+        }
+        if(root.val > value){
+            return root.val;
+        }
+        int l = traversal(root.left,value);
+        int r = traversal(root.right,value);
+
+        if(l>=0 && r>=0){
+            return Math.min(l,r);
+        }
+        return Math.max(l,r);
+    }
+
+}