1009. K-based Numbers Time limit: 0.5 secondMemory limit: 64 MB Let’s consider K-based numbers, containing exactly N digits. We define a number to be valid if itsK-based notation doesn’t contain two successive zeros. For example: 1010230 is a valid 7…

Find first K frequency numbers /* * Input: int[] A = {1, 1, 2, 3, 4, 5, 2}; k = 3 * return the highest frequency numbers. * return: [1, 2, 3] or [1, 2, 4] or [1, 2, 5] * */ 找出出现频率前k的数字 SOLUTION 1: 先将数字全放入一个map, key为数字,value为frequency, 对map排序,时间复杂度是Nl…

Given a target number, a non-negative integer k and an integer array A sorted in ascending order, find the k closest numbers to target in A, sorted in ascending order by the difference between the number and target. Otherwise, sorted in ascending ord…

Given an integer array, find the top k largest numbers in it.   Example Given [3,10,1000,-99,4,100] and k = 3. Return [1000, 100, 10]. 解法一: class Solution { public: /* * @param nums: an integer array * @param k: An integer * @return: the top k larges…

Given an integer array, find the top k largest numbers in it. Example Given [3,10,1000,-99,4,100] and k = 3.Return [1000, 100, 10]. 思路:由于需要按从大到小的顺序,因此直接用PriorityQueue即可,用Partition的方法的话还需要排序.直接用PriorityQueue 写的代码量少. class Solution { /* * @param nums a…

题目如下: Given an array of integers nums and a positive integer k, find whether it's possible to divide this array into sets of k consecutive numbersReturn True if its possible otherwise return False. Example 1: Input: nums = [1,2,3,3,4,4,5,6], k = 4 Ou…

[本文链接] http://www.cnblogs.com/hellogiser/p/find-k-missing-numbers-from-1-to-n.html  [题目] 从1到n,共有n个数字(无序排列),每个数字只出现一次.现在随机拿走一个数字x,请给出最快的方法,找到这个数字.要求时间复杂度为O(n),空间复杂度为O(1).如果随机拿走k(k>=2)个数字呢? [分析] 题目给出的条件很强,数字是从1~n的数字,限制了数字的范围:每个数字只出现一次,限制了数字出现的次数:随即拿走了一…

题目链接:http://codeforces.com/gym/101466/problem/K 题目: 题意: 给你一棵有n个节点的树,根节点始终为0,有两种操作: 1.RAND:查询以u为根节点的子树上的所有节点的权值的乘积x,及x的因数个数. 2.SEED:将节点u的权值乘以x. 思路: 比赛时少看了因数不大于13这句话,然后本题难度增加数倍,肝了两个小时都没肝出来,对不起队友啊,今天的组队训练赛实力背锅…… 这题一眼线段树,由于是对一棵子树进行处理,因此我们采用常规套路,借助dfs序将子树…

Tamref love random numbers, but he hates recurrent relations, Tamref thinks that mainstream random generators like the linear congruent generator suck. That's why he decided to invent his own random generator. As any reasonable competitive programmer…

题意:定义两个数\(a,b\)是朋友,如果:\(gcd(a,b)\),\(\frac{a}{gcd(a,b)}\),\(\frac{b}{gcd(a,b)}\)能构成三角形,现在给你一个正整数\(n\),问你\(1-n\)中有多少数没有朋友. 题解:首先考虑合数,设\(a=b*c\),\(b\ge c\),\(b\ge 2,c\ge 2\),我们知道:\(gcd(b,b-1)=1\),那么:\(gcd(b*c,(b-1)*c)=c\),则对于:\(b*c\),\((b-1)*c\),\(gcd(…