Add comprehensive LeetCode problem implementations

- Add Problem 213: House Robber II (medium) with 6 DP approaches
- Add Problem 46: Permutations (medium) with 6 backtracking approaches
- Add Problem 48: Rotate Image (medium) with matrix manipulation
- Add multiple tree and graph problems with extensive testing
- Implement comprehensive solutions with detailed explanations
- Include edge case testing and performance analysis

Author: Caia-Tech

src/easy/house_robber.rs

@@ -13,6 +13,10 @@ pub mod merge_two_sorted_lists;
 pub mod remove_duplicates_from_sorted_array;
 pub mod best_time_to_buy_and_sell_stock;
 pub mod climbing_stairs;
+pub mod maximum_depth_of_binary_tree;
+pub mod invert_binary_tree;
+pub mod subtree_of_another_tree;
+pub mod house_robber;
 // pub mod remove_element;
 // pub mod implement_strstr;
 // pub mod search_insert_position;