给定数组a[1,2,3],用a里面的元素来生成一个长度为5的数组,打印出其排列组合 ruby代码: def all_possible_arr arr, length = 5 ret = [] length.times do if ret.empty? ret = arr.map {|i| [i]} else new_ret = [] ret.each do |r| arr.each do |e| new_ret << r.clone.unshift(e) end end ret = new_r
B. Powers of Two You are given n integers a1, a2, ..., an. Find the number of pairs of indexes i, j (i < j) that ai + aj is a power of 2 (i. e. some integer xexists so that ai + aj = 2x). Input The first line contains the single positive integer n
问题描述 无序数组求第K大的数,其中K从1开始算. 例如:[0,3,1,8,5,2]这个数组,第2大的数是5 OJ可参考:LeetCode_0215_KthLargestElementInAnArray 堆解法 设置一个小根堆,先把前K个数放入小根堆,对于这前K个数来说,堆顶元素一定是第K大的数,接下来的元素继续入堆,但是每入一个就弹出一个,最后,堆顶元素就是整个数组的第K大元素.代码如下: public static int findKthLargest3(int[] nums, int k)
题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1394 Minimum Inversion Number Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 10
Minimum Inversion Number Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 13036 Accepted Submission(s): 7968 Problem Description The inversion number of a given number sequence a1, a2, ..., an
前些天看到.net笔试习题集上的一道小题,要求将1至100内的正整数随机填充到一个长度为100的数组,求一个简单的算法. 今天有空写了一下.代码如下,注释比较详细: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Text.RegularExpressions; namespace TestNumber { class Program { //定义
Musical Theme Time Limit: 1000MS Memory Limit: 30000K Total Submissions: 14874 Accepted: 5118 Description A musical melody is represented as a sequence of N (1<=N<=20000)notes that are integers in the range 1..88, each representing a key on the