fixes TheAlgorithms#11232 issue replaces global variable by instance variable

Author: GantedaAravind

Diff for: data_structures/binary_tree/segment_tree.py

@@ -98,7 +98,7 @@ def query_recursive(self, idx, l, r, a, b):  # noqa: E741
 
     def show_data(self):
         show_list = []
-        for i in range(1, N + 1):
+        for i in range(1, self.N + 1):
             show_list += [self.query(i, i)]
         print(show_list)