在数据库操作中,经常有一些这样的操作:插入诺干条测试数据.查询这个月的登录情况(没有登录的日期不能不存在,要显示数量为0),获取诺干条guid. 这些的基础都是怎么生成连续的一串数字 1 2 3 4 ……………… 100000. 在oracle中,我们使用start with connect by connect by rownum <= 在sqlserver中,由于没有现成的语法,我们可以采用cte with test as ( rn union all rn )select rn
题目来源: http://poj.org/problem?id=2255 题目描述: Description Little Valentine liked playing with binary trees very much. Her favorite game was constructing randomly looking binary trees with capital letters in the nodes. This is an example of one of her cr
根据中序和后续遍历构建二叉树. /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ class Solution { public TreeNode buildTree(int[] inorder, int[] postorder) { if(ino
python学习1-字符串数字基本运算以及if条件和while循环 字符串表达形式共四种: name = "string" name = 'string' name = """string""" name = '''string''' 数字基本运算方式: a = 39 b = 4 c = a + b c = a - b c = a*b c= a**b #次幂 c = a/b c = a%b #取余数 c = a//b #取除数