Given a string s and a string t, check if s is subsequence of t. You may assume that there is only lower case English letters in both s and t. t is potentially a very long (length ~= 500,000) string, and s is a short string (<=100). A subsequence of
Given an undirected graph, return true if and only if it is bipartite. Recall that a graph is bipartite if we can split it's set of nodes into two independent subsets A and B such that every edge in the graph has one node in A and another node in B.
Swift 语言提供经典的数组和字典两种集合类型来存储集合数据.数组用来按顺序存储同样类型的数据.字典尽管无序存储同样类型数据值可是须要由独有的标识符引用和寻址(就是键值对). Swift 语言里的数组和字典中存储的数据值类型必须明白. 这意味着我们不能把不对的数据类型插入当中. 同一时候这也说明我们全然能够对获取出的值类型很自信. Swift 对显式类型集合的使用确保了我们的代码对工作所须要的类型很清楚,也让我们在开发中能够早早地找到不论什么的类型不匹配错误. 注意: Swift 的数组结构在