浅谈关系型数据库与非关系型数据库
我们经常会接触到各种类型的数据库,比较出名的是MySQL、NoSQL,还有Redis算不算数据库呢?什么是关系型数据库,什么又是非关系型数据库?它们之间有什么区别呢?优缺点分别又是什么?
Given two lists of closed intervals, each list of intervals is pairwise disjoint and in sorted order.
Return the intersection of these two interval lists.
(Formally, a closed interval [a, b] (with a <= b) denotes the set of real numbers x with a <= x <= b. The intersection of two closed intervals is a set of real numbers that is either empty, or can be represented as a closed interval. For example, the intersection of [1, 3] and [2, 4] is [2, 3].)
A query word matches a given pattern
if we can insert lowercase letters to the pattern word so that it equals the query
. (We may insert each character at any position, and may insert 0 characters.)
Given a list of queries
, and a pattern
, return an answer
list of booleans, where answer[i]
is true if and only if queries[i]
matches the pattern
.
Given a 2D array A
, each cell is 0 (representing sea) or 1 (representing land)
A move consists of walking from one land square 4-directionally to another land square, or off the boundary of the grid.
Return the number of land squares in the grid for which we cannot walk off the boundary of the grid in any number of moves.