Json随笔

http://haohaoxuexi.iteye.com/blog/1750680 SpringMVC 中的Interceptor 拦截器也是相当重要和相当有用的，它的主要作用是拦截用户的请求并进行相应的处理。比如通过它来进行权限验证，或者是来判断用户是否登陆，或者是像12306 那样子判断当前时间是否是购票时间。 一、定义Interceptor实现类SpringMVC 中的Inte

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two

Given an integer, write a function to determine if it is a power of two.一行解决战斗：return n > 0 && (n & (n - 1)) == 0;

本博文参考自：https://leetcode.com/discuss/38206/ac-o-n-solution-in-java-using-buckets-with-explanationGiven an array of integers, find out whether there are two distinct indices i and j in the array such tha

public class Solution { class KeyPoint { public int key; public int height; public KeyPoint next = null; public KeyPoint(int key, int height) { this.key = k

Given a 2D board and a list of words from the dictionary, find all words in the board.Each word must be constructed from letters of sequentially adjacent cell, where “adjacent” cells are those horizont

Majority Element Total Accepted: 44517 Total Submissions: 127008 My Submissions Question Solution Given an array of size n, find the majority element. The majority element is the element that appears

There are a total of n courses you have to take, labeled from 0 to n - 1.Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is expressed as a pair:

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers.Ensure that numbers within

本博客参考自：https://leetcode.com/discuss/36544/simple-ac-solution-in-java-in-o-n-with-explanationNote: This is an extension of House Robber.After robbing those houses on that street, the thief has found him

Given a string S, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation.For example:G

Given a 2D binary matrix filled with 0’s and 1’s, find the largest square containing all 1’s and return its area.For example, given the following matrix:1 0 1 0 0 1 0 1 1 1 1 1 1 1 1 1 0 0 1 0 Retu

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 with value 3, t

Given an array containing n distinct numbers taken from 0, 1, 2, …, n, find the one that is missing from the array.For example, Given nums = [0, 1, 3] return 2.Note: Your algorithm should run in line

Given two strings s and t, write a function to determine if t is an anagram of s.For example, s = “anagram”, t = “nagaram”, return true. s = “rat”, t = “car”, return false.Note: You may assume the s

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.找到一个字符串中最大的回文子字符串程序来自：https

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, where in

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)).这道题目看似比较简单，做起来才发现暗藏玄机。。。。这道题的一

Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, …) which sum to n.For example, given n = 12, return 3 because 12 = 4 + 4 + 4; given n = 13, return

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. For “

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 linke

H-Index IGiven an array of citations (each citation is a non-negative integer) of a researcher, write a function to compute the researcher’s h-index.According to the definition of h-index on Wikipedia:

You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is developed based on the

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 of nums except nums[i].Solve it without division and in O(n).For e

Given an array nums, there is a sliding window of size k which is moving from the very left of the array to the very right. You can only see the k numbers in the window. Each time the sliding window mo

Write a program to check whether a given number is an ugly number.Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 6, 8 are ugly while 14 is not ugly since it in

Design a data structure that supports the following two operations:void addWord(word) bool search(word) search(word) can search a literal word or a regular expression string containing only letters a

Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.For example, Given [3,2,1,5,6,4] and k = 2, return 5.Note:

Given a complete binary tree, count the number of nodes.Definition of a complete binary tree from Wikipedia: In a complete binary tree every level, except possibly the last, is completely filled, and

Two elements of a binary search tree (BST) are swapped by mistake.Recover the tree without changing its structure.Note: A solution using O(n) space is pretty straight forward. Could you devise a const

Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.Below is one possible representation of s1 = “great”:great / \ gr eat / \

Given two strings s and t, determine if they are isomorphic.Two strings are isomorphic if the characters in s can be replaced to get t.All occurrences of a character must be replaced with another chara

Description:Count the number of prime numbers less than a non-negative number, n题意非常简单，给定一个非负数n，返回小于等于n 的素数的个数。看了题，so easy，直接造，第一版程序如下： public int countPrimes0(int n) { int rst=0; for

Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.)You have the following 3 operations permitted on a word:a) In

You are given a string, S, and a list of words, L, that are all of the same length. Find all starting indices of substring(s) in S that is a concatenation of each word in L exactly once and without any

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 one candy.

Given a string s, partition s such that every substring of the partition is a palindrome.Return the minimum cuts needed for a palindrome partitioning of s.For example, given s = “aab”, Return 1 since

Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND of all numbers in this range, inclusive.For example, given the range [5, 7], you should return 4.Credits: Special thanks to

Remove all elements from a linked list of integers that have value val.Example Given: 1 –> 2 –> 6 –> 3 –> 4 –> 5 –> 6, val = 6 Return: 1 –> 2 –> 3 –> 4 –> 5Credits: Special thanks to @mithmatt for a

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 none) of