KiKi's K-Number Time Limit: 4000/2000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 2546 Accepted Submission(s): 1174 Problem Description For the k-th number, we all should be very familiar with it. Of course,t
D. Distance in Tree time limit per test 3 seconds memory limit per test 512 megabytes input standard input output standard output A tree is a connected graph that doesn't contain any cycles. The distance between two vertices of a tree is the length (
first def first(): T first返回RDD中的第一个元素,不排序. 例子: count def count(): Long count返回RDD中的元素数量 例子: reduce def reduce(f: (T, T) ⇒ T): T 根据映射函数f,对RDD中的元素进行二元计算,返回计算结果(可用于求和,字符串叠加等等) 例子: take def take(num: Int): Array[T] take用于获取RDD中从0到num-1下标的元素,不排序 例子: top