代码 class Solution: def isValid(self, s: str) -> bool: while True: if '[]' in s: s = s.replace('[]', '') elif '{}' in s: s = s.replace('{}', '') elif ...
给定结点数n，结点值为1，2，...，n，求由这些结点可以构成的所有二叉查找树。Given n, generate all structurally unique BST's (binary search trees) that store values 1...n.For example, Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 ...
Error:cannot solve it. So stupid.Use dfs to solve it. Actually we can use BFS, which is simpler. But I think dfs is something we use mostly. In dfs, iterate all node, then cou
Word Break Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.For example, givens = "leetcod
