ziquanbang的专栏

一次偶然的机会，同学接触到一个函数，可以将一串字符串中的逗号以及"-"除去，当然，并不是简单地除去这两个符号。例如 1,2,3,4    处理后变为 1 2 3 41-3,4       处理后变为 1 2 3 4诸如此类的功能。好吧，后面的时间开始编程实现。

Reverse a linked list from position m to n. Do it in-place and in one-pass.For example:Given 1->2->3->4->5->NULL, m = 2 and n = 4,return 1->4->3->2->5->NULL.Note:Given m, n satisfy t

Given an array and a value, remove all instances of that value in place and return the new length.The order of elements can be changed. It doesn't matter what you leave beyond the new length.

Implement strStr().Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.思路：KMP算法

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.思路，采用小顶堆/** * Definition for singly-linked list. * struct ListNode { * int val; *

Given a linked list, reverse the nodes of a linked list k at a time and return its modified list.If the number of nodes is not a multiple of k then left-out nodes in the end should remain as it is

Given a linked list, swap every two adjacent nodes and return its head.For example,Given 1->2->3->4, you should return the list as 2->1->4->3.Your algorithm should use only constant space. Y

Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note:Elements in a triplet (a,b,c

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for "abcabcbb" is "abc", which the length is 3. Fo

There are two sorted arrays A and B of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).方法一：先合并数组，在排序，在搜索中间值。（繁琐）方法二：可以

Reverse digits of an integer.Example1: x = 123, return 321Example2: x = -123, return -321class Solution {public: int reverse(int x) { bool sign = x > 0 ? false : true; /

xxxThe string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)P A H NA

Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring.从每个位置，向两边开始扫描。

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

unordered_map 被推荐取代hash map，其被包含在头文件中，leetcode 第一题可用。

cmath是c++语言中的库函数，类似于C语言的math.h头文件常用的math函数 有  求幂，求对数，求余，等等。using ::abs; //绝对值using ::acos; //反余弦using ::acosf; //反余弦using ::acosl; //反余弦using ::asin; //反正弦using ::a

1.  Two sum   Given an array of integers, find two numbers such that they addup to a specific target number.The function twoSum should return indices of the two numberssuch that they add up to t