217. Contains Duplicate Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct. 判断数组是是否含有重复元素.…

Remove Duplicate Letters I Given a string which contains only lowercase letters, remove duplicate letters so that every letter appear once and only once. Example: Given "bcabc"Return "abc" Given "cbacdcbc"Return "abcd&qu…

Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k. Example 1: Input: nums = [1,2,3,1], k = 3 Output:…

题目: ​ 给定一个整数数组和一个整数 k,判断数组中是否存在两个不同的索引 i 和 j,使得 nums [i] = nums [j],并且 i 和 j 的差的绝对值最大为 k. ​ Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute…

思路:滑动窗口(长度为k+1)看这个窗口里的是否有两个元素的值相同.加查找表. //时间:O(n) //空间:O(k) class Solution { public: bool containsNearbyDuplicate(vector<int>& nums, int k) { unordered_set<int> record; //查找表 ; i<nums.size();i++) { if(record.find(nums[i])!= record.end()…

39. Combination Sum Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The same repeated number may be chosen from C unlimited number of times. Note: All numbers (inc…

Strobogrammatic Number A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down). Write a function to determine if a number is strobogrammatic. The number is represented as a string. For example, the nu…

题目1:Best Time to Buy and Sell Stock Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algori…

Given an array of integers, find out whether there are two distinct indices i and j in the array such that the difference between nums[i] and nums[j] is at most t and the difference between i and j is at most k. 这道题跟之前两道Contains Duplicate 包含重复值和Conta…

待整理 对于基于生产环境下的数据库的版本升级或者测试新的应用程序的性能及其影响,备份恢复等等,我们可以采取从生产环境以克隆的方式将其克隆到本地而不影响生产数据库的正常使用.实现这个功能我们可以借助rman duplicate方式以及其简单的方式来完成.duplicate方式不同于OS级别的备份,它会为辅助数据库(克隆出来的数据库)生成一个新的dbid,而能够同时将目标数据库(原数据库)与辅助数据库注册到同一个恢复目录.本文描述了使用rman duplicate实现异机数据库克隆. 1.RMAN支…