典型动态规划： 64.最小路径和 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/64_Minimum_Path_sum.py
62.不同路径 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/62_Unique_paths.py
139.单词拆分 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/139_Word_break.py
413.等差数列 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/413_Arithmetic_slices.py
647.回文子串 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/647_Palindromic_substrings.py
剪绳子问题 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/343_Integer_break.py
dfs： 46.全排列 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/46_Permutations.py
77.组合 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/77_Combinations.py
1319.并查集 C++ https://github.com/ziqinXU/Leetcode/blob/master/Medium/1319_Number_of_operations_to_make_network_connected.cpp 416.01背包问题类似 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/416_Partition_equal_subset_sum.py
518.完全背包问题 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/518_Coin_change_2.py
322.零钱兑换 动态规划 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/322_Coin_change.py
377.动态规划-组合总和 https://github.com/ziqinXU/Leetcode/blob/master/Medium_Python/377_Combination_sum_IV.py 位运算:136.只出现一次的数字 137.只出现一次的数字II 1552.二分法+贪心 https://github.com/ziqinXU/Leetcode/blob/master/Medium/1552_Magnetic_force_between_two_balls.cpp
144.二叉树前序遍历 https://github.com/ziqinXU/Leetcode/blob/master/Medium/144_Binary_tree_preorder_traversal.cpp