u010667357的专栏

Implement atoi to convert a string to an integer.Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input ca

A message containing letters from A-Z is being encoded to numbers using the following mapping:'A' -> 1'B' -> 2...'Z' -> 26Given an encoded message containing digits, determine the total nu

Given a string containing only digits, restore it by returning all possible valid IP address combinations.For example:Given "25525511135",return ["255.255.11.135", "255.255.111.35"]. (Order

Given a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n).For example,S = "ADOBECODEBANC"T = "ABC"Minimum window is "BANC"

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.

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 the

对象的序列化与Serializable 接口1. 基本的序列化操作    一般来说，对象只存在与进程运行期间，进程中止后，你所创建的对象就灰飞烟灭。但是有的时候，你需要在程序中止后继续保留对象信息，这样下次运行时，你可以将对象重建恢复到程序上次运行时它所拥有的信息。    Java中提供了Serializable接口来标记可序列化的对象。public interface Ser

Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of a node contains only nodes with keys less than the node's key.

原题地址：https://oj.leetcode.com/problems/recover-binary-search-tree/Two elements of a binary search tree (BST) are swapped by mistake.Recover the tree without changing its structure.Note:

Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area.将二维的问题转换为一维问题

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)).

Insertion Sort List Total Accepted: 18506 Total Submissions: 73505 My SubmissionsSort a linked list using insertion sort.链表的插入排序，没什么

Sort a linked list in O(n log n) time using constant space complexity.public class SortList { static class ListNode { int val; ListNode next; ListNode(int x) { val =

Max Points on a Line Total Accepted: 16037 Total Submissions: 148156 My SubmissionsGiven n points on a 2D plane, find the maximum number of points that lie on the same straight line.

Given an absolute path for a file (Unix-style), simplify it.For example,path = "/home/", => "/home"path = "/a/./b/../../c/", => "/c"public class Solution { public String simplifyPath

Given two binary strings, return their sum (also a binary string).For example,a = "11"b = "1"Return "100".

Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.Above is a histogram where width o

Evaluate the value of an arithmetic expression in Reverse Polish Notation.Valid operators are +, -, *, /. Each operand may be an integer or another expression.Some examples:["2", "1", "+", "

Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.For example,Given:s1 = "aabcc",s2 = "dbbca",When s3 = "aadbbcbcac", return true.When s3 = "aadbbbaccc", r

原题地址：https://oj.leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/Given inorder and postorder traversal of a tree, construct the binary tree.Note:You may assume

原题地址：https://oj.leetcode.com/problems/longest-substring-without-repeating-characters/Given a string, find the length of the longest substring without repeating characters. For example, the longe

Next Permutation Total Accepted: 14635 Total Submissions: 57694 My SubmissionsImplement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.

Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.OJ's undirected graph serialization:Nodes are labeled uniquely.We use # as a separator for ea

题目：给定一组长短不一的棍子，求能组成的周长最长的三角形。分析：

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] of gas to travel from station i to it

There are N children standing in a line. Each child is assigned a rating value.You are giving candies to these children subjected to the following requirements:Each child must have at least on

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.Return a deep copy of the list.

Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and set.get(key) - Get the value (will always be positive) of the key if

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.递归

思路：和《剑指OFFER》中求丑数的题目很像，序列中第N个数 必然是是前N - 1个数乘以 2 或者乘以5 中大于第N - 1个数的最小值。可以通过分别标记上次乘以2 或乘以5的位置开始寻找被乘数。取最小值，如果 乘以2 的小 则第N个数为该数，同时将2的标记位置右移一位，同理乘以5小时右移5的标记位置，二者相同时同时右移两位。显然，肯定能保证所得数比上一个数大。

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.For example, given the array [−2,1,−3,4,−1,2,1,−5,4],the contiguous subarray [4,−1,2,1] ha

原题链接： https://oj.leetcode.com/problems/longest-consecutive-sequence/Given an unsorted array of integers, find the length of the longest consecutive elements sequence.For example,Given 

Given a string S and a string T, count the number of distinct subsequences of T in S.A subsequence of a string is a new string which is formed from the original string by deleting some (can be non

Given a 2D board containing 'X' and 'O', capture all regions surrounded by 'X'.A region is captured by flipping all 'O's into 'X's in that surrounded region.For example,X X X XX O O X

二叉树的先序、中序、后序、层次遍历的递归和非递归解法package tree;import java.util.LinkedList;import java.util.Queue;import java.util.Stack;public class TreeTraverse { /** * 先序递归 * @param root */ public stat

原题地址：https://oj.leetcode.com/problems/word-ladder/

原题地址：https://oj.leetcode.com/problems/palindrome-partitioning-ii/Given a string s, partition s such that every substring of the partition is a palindrome.Return the minimum cuts needed for a palin

题目链接：https://oj.leetcode.com/problems/word-break-ii/Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word.Return all

JAVA中ArrayList 和 Vector 比较：    1. API    从提供API来看，二者几乎一致，vector多了element系列API，如elementAt()、firstElement()等。但实现的功能基本一致，故如果需要选择的时候API的差别不应该一个重要的参考项    2. 线程同步    Vector的每个方法都是线程同步的，因此当需要