Create Closest Nodes Queries in a Binary Search Tree.java

varunu28 · web-flow · commit 1812e49c10a7 · 2022-11-20T08:54:46.000-08:00
diff --git a/Medium/Closest Nodes Queries in a Binary Search Tree.java b/Medium/Closest Nodes Queries in a Binary Search Tree.java
@@ -0,0 +1,37 @@
+/**
+ * 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 {
+    public List<List<Integer>> closestNodes(TreeNode root, List<Integer> queries) {
+        TreeSet<Integer> set = new TreeSet<>();
+        traverse(root, set);
+        List<List<Integer>> result = new ArrayList<>();
+        for (Integer query : queries) {
+            Integer lower = set.floor(query);
+            Integer upper = set.ceiling(query);
+            result.add(Arrays.asList((lower == null ? -1 : lower), (upper == null ? -1 : upper)));
+        }
+        return result;
+    }
+    
+    private void traverse(TreeNode root, TreeSet<Integer> set) {
+        if (root == null) {
+            return;
+        }
+        set.add(root.val);
+        traverse(root.left, set);
+        traverse(root.right, set);
+    }
+}
