摘要:
Given n, how many structurally unique BST's (binary search trees) that store values 1...n?For example,Given n = 3, there are a total of 5 unique BST's... 阅读全文
摘要:
if want lexicographic order,然后要用Collections.sort() 来保证字典序 for (List<String> each : map.values()) { Collections.sort(each); res.add(new ArrayList<Strin 阅读全文