Update README.md

Author: zjkang

python/dp/README.md

@@ -1,5 +1,7 @@
 #### dp 更新
 
+dp可以分为序列型dp,区间第一类型dp,区间第二类型dp,背包问题。
+
 [Laicode 456 Coin Change (M)](https://github.com/zjkang/ds_algorithm/blob/main/python/dp/laicode_0456_coin_change.py)\
 [Laicode 663 Coin Change II (M)](https://github.com/zjkang/ds_algorithm/blob/main/python/dp/laicode_0663_coin_change_ii.py)\
 [Leetcode 416 Partition Equal Subset Sum (M)](https://github.com/zjkang/ds_algorithm/blob/main/python/dp/leetcode_0416_partition_equal_subset_sum.py)\