摘要:
题目大意: Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally ident 阅读全文
摘要:
栈的相关操作。 public class Solution { public boolean isValid(String s) { if(s == "") return true; Stack<Character> st = new Stack<Character>(); st.push(s.ch 阅读全文