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原创 203. Remove Linked List Elements

Remove all elements from a linked list of integers that have valueval. Example: Input: 1->2->6->3->4->5->6, val = 6 Output: 1->2->3->4->5 /** * Definition for ...

2020-05-05 16:02:18 98

原创 8. String to Integer (atoi)

Implement atoi whichconverts a string to an integer. The function first discards as many whitespace characters as necessary until the first non-whitespace character is found. Then, starting from thi...

2020-05-05 16:00:37 66

原创 7. Reverse Integer

Given a 32-bit signed integer, reverse digits of an integer. Example 1: Input: 123 Output: 321 Example 2: Input: -123 Output: -321 Example 3: Input: 120 Output: 21 Note: Assume we are dealing with...

2019-12-16 14:00:42 75

原创 5. Longest Palindromic Substring

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example 1: Input: "babad" Output: "bab" Note: "aba" is also a valid answer. Exampl...

2019-12-13 18:34:39 80

原创 3. Longest Substring Without Repeating Characters

Given a string, find the length of the longest substring without repeating characters. Example 1: Input: "abcabcbb" Output: 3 Explanation: The answer is "abc", with the length of 3. Example 2: In...

2019-12-13 14:32:27 64

原创 2. Add Two Numbers

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return i...

2019-11-07 17:05:14 57

原创 1. Two sum

题目描述给定一个整型数组，要求返回两个数的下标，使得两数之和等于给定的目标值，要求同一个下标不能使用两次。数据保证有且仅有一组解。样例给定数组 nums = [2, 7, 11, 15]，以及目标值 target = 9，由于 nums[0] + nums[1] = 2 + 7 = 9, 所以 return [0, 1]. 算法1: （暴力枚举）O(n^2) 使用两个循环实...

2019-11-06 16:44:03 108

原创机器学习实战笔记一：kNN分类算法

开发机器学习应用程序的步骤： 1、收集数据 2、准备输入数据 3、分析输入数据 4、训练算法 5、测试算法 6、使用算法第一个算法：k-近邻算法 k-近邻算法的一般流程： 1、收集数据：可以使用任何方法 2、准备数据：距离计算所需要的数值，最好是结构化的数据格式，此时需要对数据进行格式化 3、分析数据：可以使用任何方法 4、训练算法：此步骤不适合用于k-近

2017-03-23 20:41:43 324

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