From 9bc05f81fe3e5bb53be7a6ee1e7a0a66676b2d94 Mon Sep 17 00:00:00 2001
From: Harsh Kumar <54257619+iamharshkr@users.noreply.github.com>
Date: Tue, 17 Oct 2023 21:36:23 +0530
Subject: [PATCH] Create Diagonal sum in BST.java

---
 Searching/Diagonal sum in BST.java | 76 ++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 Searching/Diagonal sum in BST.java

diff --git a/Searching/Diagonal sum in BST.java b/Searching/Diagonal sum in BST.java
new file mode 100644
index 0000000..4d2afd0
--- /dev/null
+++ b/Searching/Diagonal sum in BST.java	
@@ -0,0 +1,76 @@
+//Find the diagonal sum of a binary tree
+import java.util.HashMap;
+import java.util.Map;
+ 
+// A class to store a binary tree node
+class Node
+{
+    int data;
+    Node left = null, right = null;
+ 
+    Node(int data) {
+        this.data = data;
+    }
+}
+ 
+class Main
+{
+    // Recursive function to perform preorder traversal on the tree and
+    // fill the map with the diagonal sum of elements
+    public static void diagonalSum(Node root, int diagonal, Map<Integer, Integer> map)
+    {
+        // base case: empty tree
+        if (root == null) {
+            return;
+        }
+ 
+        // update the current diagonal with the node's value
+        map.put(diagonal, map.getOrDefault(diagonal, 0) + root.data);
+ 
+        // recur for the left subtree by increasing diagonal by 1
+        diagonalSum(root.left, diagonal + 1, map);
+ 
+        // recur for the right subtree with the same diagonal
+        diagonalSum(root.right, diagonal, map);
+    }
+ 
+    // Function to print the diagonal sum of a given binary tree
+    public static void diagonalSum(Node root)
+    {
+        // create an empty map to store the diagonal sum for every slope
+        Map<Integer, Integer> map = new HashMap<>();
+ 
+        // traverse the tree in a preorder fashion and fill the map
+        diagonalSum(root, 0, map);
+ 
+        // traverse the map and print the diagonal sum
+        System.out.println(map.values());
+    }
+ 
+    public static void main(String[] args)
+    {
+        /* Construct the following tree
+                   1
+                 /   \
+                /     \
+               2       3
+              /      /  \
+             /      /    \
+            4      5      6
+                  / \
+                 /   \
+                7     8
+        */
+ 
+        Node root = new Node(1);
+        root.left = new Node(2);
+        root.right = new Node(3);
+        root.left.left = new Node(4);
+        root.right.left = new Node(5);
+        root.right.right = new Node(6);
+        root.right.left.left = new Node(7);
+        root.right.left.right = new Node(8);
+ 
+        diagonalSum(root);
+    }
+}