u010455041的专栏

题目：      Rotate an array of n elements to the right by k steps.      For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].      Note:      Try to

题目：          Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times.           You may assume that the array is non-emp

题目：               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.

题目：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

题目：Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.解题思路：# Definition for singly-linked list.# c

题目：Remove all elements from a linked list of integers that have value val.ExampleGiven: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6Return: 1 --> 2 --> 3 --> 4 --> 5代码：# Definition

题目：Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.解题思路：(1)、二分法(accept)此法比较巧妙，当时没有想起用这个方法。复杂度为O(nlgn)# Definition for singly-linked list

题目：Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.You should preserve the original relative order of the nodes i

题目：Given a sorted linked list, delete all duplicates such that each element appear only once.For example,Given 1->1->2, return 1->2.Given 1->1->2->3->3, return 1->2->3.代码：此题简单，但未一次通过

题目：Given a linked list, remove the nth node from the end of list and return its head.For example, Given linked list: 1->2->3->4->5, and n = 2. After removing the second node from the

题目：Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.For example,Given 1->2->3->3->4->4->5, return 1->2->5.Gi

题目：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

题目：Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST.解题思路：具体思路即为，每次查找到中间的节点，将其作为树的根节点，以该点切分，其左侧以及右侧皆采用此方法，最终即构建出来所需的树。边界条件需要多加注意。此题思路

题目：Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would hav

题目：         There are two sorted arrays nums1 and nums2 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)).解题思路： 

题目：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

题目：       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.解题思路：

题目：      Reverse digits of an integer.Example1: x = 123, return 321Example2: x = -123, return -321解题思路：此题极为简单，但有一个小陷阱。附链接https://leetcode.com/discuss/28079/one-python-test-case-i

题目：Determine whether an integer is a palindrome. Do this without extra space.解题思路：           此题有两种解法，一种可以用递归方式，很容易理解。另一张就是迭代方式。由于此题要求不能有额外的空间开销。故使用迭代，但在此说明一下         (1)、 递归方式class Solutio

题目：Given an array of integers, find two numbers such that they add up to a specific target number.The function twoSum should return indices of the two numbers such that they add up to the target

题目：       Given a non-negative number represented as an array of digits, plus one to the number.     The digits are stored such that the most significant digit is at the head of the list.解题思路：

题目：Given an array of integers and an integer k, find out whether there there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between iand j is at

题目：Given a sorted integer array without duplicates, return the summary of its ranges.For example, given [0,1,2,4,5,7], return ["0->2","4->5","7"].解题思路：class Solution:    # @param {inte

题目：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

题目：Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times. The algorithm should run in linear time and in O(1) space.解题思路：class Solution:    # @param {in

题目：Given a set of distinct integers, nums, return all possible subsets.Note:Elements in a subset must be in non-descending order.The solution set must not contain duplicate subsets.For e

题目：Given a collection of integers that might contain duplicates, nums, return all possible subsets.Note:Elements in a subset must be in non-descending order.The solution set must not contain

题目：Reverse a singly linked list.Hint:A linked list can be reversed either iteratively or recursively. Could you implement both?解题思路：(1)、迭代版分析以上代码，一开始时我是将head=head.next放在一

题目：Given a list, rotate the list to the right by k places, where k is non-negative.For example:Given 1->2->3->4->5->NULL and k = 2,return 4->5->1->2->3->NULL.解题思路：我在解此题时，遇到的最大问题是没能完全

题目：Count the number of prime numbers less than a non-negative number, n.解题思路：思路一（Time limit Exceed）：class Solution:    # @param {integer} n    # @return {integer}    def countPrimes(se

题目：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 

题目：Implement a basic calculator to evaluate a simple expression string.The expression string may contain open ( and closing parentheses ), the plus + or minus sign -, non-negative integers

题目：Implement a basic calculator to evaluate a simple expression string.The expression string contains only non-negative integers, +, -, *, / operators and empty spaces . The integer divisi

题目：Implement the following operations of a queue using stacks.push(x) -- Push element x to the back of queue.pop() -- Removes the element from in front of queue.peek() -- Get the front eleme

题目：Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node

题目：Given a singly linked list, determine if it is a palindrome.Follow up:Could you do it in O(n) time and O(1) space?解题思路：可以分为以下几步：1、计算链表的长度L，直接遍历即可。2、若L为0或1，则是回文的链表。3、

题目：Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.If the last word does not exist, return 0.Note: 

题目：Given an array of n integers where n > 1, nums, return an array output such that output[i] is equal to the product of all the elements ofnums except nums[i].Solve it without division 

题目：Given an unsorted integer array, find the first missing positive integer.For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2.Your algorithm should run in O(n) time and uses

题目：Reverse bits of a given 32 bits unsigned integer.For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as0