272,Closest Binary Search Tree Value II,50.5%,Hard,0.3195226783074397, https://leetcode.com/problems/closest-binary-search-tree-value-ii
828,Count Unique Characters of All Substrings of a Given String,45.2%,Hard,0, https://leetcode.com/problems/count-unique-characters-of-all-substrings-of-a-given-string