[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

divide_and_conquer/graphcolor.py

@@ -1,6 +1,7 @@
 from collections import defaultdict
 from typing import dict, list
 
+
 class Graph:
     def __init__(self, subjects: list[str]) -> None:
         """
@@ -40,11 +41,11 @@ def graph_coloring(self) -> dict[str, int]:
                 available_colors.add(color_map[subject])
         return color_map
 
-
     def get_minimum_time_slots(self) -> int:
         color_map = self.graph_coloring()
         return max(color_map.values())
 
+
 # Example usage
 subjects = ["Math", "Physics", "Chemistry", "Biology"]
 students = {
@@ -62,4 +63,5 @@ def get_minimum_time_slots(self) -> int:
 # Example doctest for add_edge method
 if __name__ == "__main__":
     import doctest
+
     doctest.testmod()