Update binary_tree_path_sum.py

Author: Aniketmishra0

data_structures/binary_tree/data_structures/binary_tree/binary_tree_path_sum.py

@@ -1 +1,22 @@
+  class Solution:
+     def pathSum(self, root: TreeNode, sum: int) -> int:
 
+         global result
+         result = 0
+
+         def dfs(node, target):
+             if node is None: return
+             find_path_from_node(node, target)
+             dfs(node.left, target)
+             dfs(node.right, target)
+
+         def find_path_from_node(node, target):
+             global result
+             if node is None: return
+             if node.val == target: result += 1
+             find_path_from_node(node.left, target-node.val)
+             find_path_from_node(node.right, target-node.val)
+
+         dfs(root, sum)
+
+         return result