solve kth smallest element in a bst

Author: sora0319

kth-smallest-element-in-a-bst/sora0319.java

@@ -0,0 +1,20 @@
+public class Solution {
+    private int count = 0;
+    private int answer = -1;
+
+    public int kthSmallest(TreeNode root, int k) {
+        ordering(root, k);
+        return answer;
+    }
+
+    private void ordering(TreeNode node, int k) {
+        if (node == null) return;
+        ordering(node.left, k);
+        count++;
+        if (count == k) {
+            answer = node.val;
+            return;
+        }
+        ordering(node.right, k);
+    }
+}