1.原问题 给定一个数组,求这个数组的连续子数组中,最大的那一段的和.如数组[-2,1,-3,4,-1,2,1,-5,4] 的子段为:[-2,1].[1,-3,4,-1].[4,-1,2,1].….[-2,1,-3,4,-1,2,1,-5,4],和最大的是[4,1,2,1],为6. 2.子问题 只考虑第一个元素,则最大子段和为其本身 DP[0] = nums[0] 考虑前两个元素,最大子段和为 nums[0],num[1]以及 nums[0] + num[1] 中最大值 设为DP[1] 考虑前三…

题意: 给一个序列,求至少含一个元素的最大子段和? 思路: 跟求普通的最大子段和差不多,只不过需要注意一下顺序.由于至少需要一个元素,所以先将ans=nums[0].接下来可以用sum求和了,如果小于0就重置为0,表示重新开始累加.注意代码中两个if的顺序不可以呼唤. class Solution { public: int maxSubArray(vector<int>& nums) { , ans=nums[]; ; i<nums.size(); i++) { sum+=nu…

Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may complete at most two transactions. Note:You may not engage in multiple transactions at the same time (ie,…

LeetCode: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 a…

Valid Palindrome吐槽一下Leetcode上各种不定义标准的输入输出(只是面试时起码能够问一下输入输出格式...),此篇文章不是详细的题解,是自己刷LeetCode的一个笔记吧,尽管没有代码,可是略微难一点的都会标出主要思路,便于以后复习 PS:题目中有"水题"两字的都是一遍AC,没有标注的都说明了问题,顺序依照Leetcode上时间倒序排列,少量题目因为和之前的题目有相关性,因此将其放在一起,比方12题和13题,因此中间可能会"缺少"几道题目,缺少的…

Best Time to Buy and Sell Stock I 题目链接 题目要求: 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…

子集和问题:给定一组数和一个值,从这组数中选出若干个数使其和为给定的值.这是个NPC问题. 1.https://leetcode.com/problems/counting-bits/#/solutions 给定一非负Integer num,求[0,num]每个数的二进制形式中1的个数  f[num+1]. 解法:可用最朴素的方法逐个求,但其实有规律: f[i] = f[i / ] + i % 或  f[i] = f[i&(i-)] + ; 2.Single Number:一组Integer类型…

前言   [LeetCode 题解]系列传送门:  http://www.cnblogs.com/double-win/category/573499.html   1.题目描述 There are N gas stations along a circular route, where the amount of gas at station i is gas[i]. You have a car with an unlimited gas tank and it costs cost[i]…

643. 子数组最大平均数 I 643. Maximum Average Subarray I 题目描述 给定 n 个整数,找出平均数最大且长度为 k 的连续子数组,并输出该最大平均数. LeetCode643. Maximum Average Subarray I 示例 1: 输入: [1,12,-5,-6,50,3], k = 4 输出: 12.75 解释: 最大平均数 (12-5-6+50)/4 = 51/4 = 12.75 注意: 1 <= k <= n <= 30,000. 所…

链接:https://leetcode.com/tag/divide-and-conquer/ [4]Median of Two Sorted Arrays [23]Merge k Sorted Lists [53]Maximum Subarray (2019年1月23日, 谷歌tag复习) 最大子段和. 题解: follow up 是divide and conquer If you have figured out the O(n) solution, try coding another…