diff --git a/src/MaximumDifferenceBetweenNodeandAncestor1026.java b/src/MaximumDifferenceBetweenNodeandAncestor1026.java
new file mode 100644
index 0000000..19a9dda
--- /dev/null
+++ b/src/MaximumDifferenceBetweenNodeandAncestor1026.java
@@ -0,0 +1,43 @@
+/**
+ * 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 {
+    int res=Integer.MIN_VALUE;
+    int max(TreeNode root)
+    {
+        if(root==null) return Integer.MIN_VALUE;
+        if(root.left==null && root.right==null) return root.val;
+        int l=max(root.left);
+        int r=max(root.right);
+        int m=Math.max(l,r);
+        res=Math.max(res,Math.abs(root.val-m));
+        return Math.max(root.val,m);
+    }
+    int min(TreeNode root)
+    {
+        if(root==null) return Integer.MAX_VALUE;
+        if(root.left==null && root.right==null) return root.val;
+        int l=min(root.left);
+        int r=min(root.right);
+        int m=Math.min(l,r);
+        res=Math.max(res,Math.abs(root.val-m));
+        return Math.min(root.val,m);
+    }
+    public int maxAncestorDiff(TreeNode root) {
+        max(root);
+        min(root);
+        return res;
+    }
+}
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