- 博客(243)
- 资源 (6)
- 收藏
- 关注
RSS订阅原创 Android消息机制，从Java层到Native层剖析
由Handler、MessageQueue、Looper构成的线程消息通信机制在Android开发中非常常用，不过大部分人都只粗浅地看了Java层的实现，对其中的细节不甚了了，这篇博文将研究Android消息机制从Java层到Native层的实现。消息机制由于更贴近抽象设计，所以整个结构更简单，只包含了消息的产生、分发，不像Input子系统那样还有归类、过滤等环节。整体的结构如下图：Android
2017-10-08 16:37:33
2043
原创 Android App启动流程
前言在使用Android手机时，我们总会启动各种各样的App以满足生活的各种需求，你是否想过，我们是怎样启动这些APP的？今天我将带着读者一起探索在Android系统中，一个App是如何被启动的。在开始分析之前，我们先回想下启动一个App的流程：Android系统桌面->点击应用图标->启动App从这个过程来看，只要弄明白：Android系统桌面是什么点击应用图标后Android系统执行了什么操
2017-02-28 12:34:51
3085
原创 LeetCode题解：Maximum Subarray
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] has the
2016-03-04 09:22:17
571
原创 LeetCode题解：Kth Smallest Element in a BST
Given a binary search tree, write a function kthSmallest to find the kth smallest element in it.Note: You may assume k is always valid, 1 ≤ k ≤ BST’s total elements.Follow up: What if the BST is mod
2016-03-04 09:16:50
622
原创 LeetCode题解：Linked List Cycle
/** * Definition for singly-linked list. * class ListNode { * int val; * ListNode next; * ListNode(int x) { * val = x; * next = null; * } * } */ pub
2016-03-04 09:02:01
423
原创 LeetCode题解：Maximum Product of Word Lengths
Given a string array words, find the maximum value of length(word[i]) * length(word[j]) where the two words do not share common letters. You may assume that each word will contain only lower case lette
2016-03-01 17:05:58
468
原创 LeetCode题解：Binary Tree Preorder Traversal
Given a binary tree, return the preorder traversal of its nodes’ values.For example: Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [1,2,3].题意：先序遍历思路：代码：/** * Definition for a
2016-03-01 16:49:40
390
原创 LeetCode题解：Missing Number
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
2016-03-01 16:48:25
494
原创 LeetCode题解：Bulb Switcher
There are n bulbs that are initially off. You first turn on all the bulbs. Then, you turn off every second bulb. On the third round, you toggle every third bulb (turning on if it’s off or turning off i
2016-03-01 16:37:47
573
原创 LeetCode题解：Best Time to Buy and Sell Stock with Cooldown
Say you have an array for which the ith element is the price of a given stock on day i.Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one and
2016-03-01 15:51:54
420
原创 LeetCode题解：Product of Array Except Self
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
2016-03-01 15:47:31
669
原创 LeetCode题解：Single Number III
Given an array of numbers nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find the two elements that appear only once.For example:Given nums = [1,
2016-03-01 15:32:49
430
原创 LeetCode题解：Single Number II
Given an array of integers, every element appears three times except for one. Find that single one.Note: Your algorithm should have a linear runtime complexity. Could you implement it without using ex
2016-03-01 15:22:33
390
原创 LeetCode题解：Min Stack
Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.push(x) – Push element x onto stack. pop() – Removes the element on top of the stack. top() – Get the
2016-02-29 09:42:08
514
原创 LeetCode题解：First Bad Version
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
2016-02-29 09:31:00
410
原创 LeetCode题解：Range Sum Query - Immutable
Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.Example: Given nums = [-2, 0, 3, -5, 2, -1]sumRange(0, 2) -> 1 sumRange(2, 5) -> -1 sumRange(0, 5
2016-02-28 15:17:37
381
原创 LeetCode题解：Binary Tree Paths
Given a binary tree, return all root-to-leaf paths.For example, given the following binary tree:1 / \ 2 3 \ 5 All root-to-leaf paths are:[“1->2->5”, “1->3”]题意：给定二叉树，返回所有路径思路：DFS代码：/** *
2016-02-28 15:03:06
321
原创 LeetCode题解：Remove Linked List Elements
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 –> 5题意：移除链表中所有给定值的结点思路：……代码：/** * Definition f
2016-02-28 15:00:35
295
原创 LeetCode题解：Word Pattern
Given a pattern and a string str, find if str follows the same pattern.Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in str.Examples:
2016-02-28 14:56:50
526
原创 LeetCode题解：Bulls and Cows
You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the number is. Each time your friend makes a guess, you provide a hint that
2016-02-28 14:47:11
576
原创 LeetCode题解：Isomorphic Strings
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
2016-02-28 11:05:57
394
原创 LeetCode题解：Reverse Bits
Reverse bits of a given 32 bits unsigned integer.For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as 00111001011110
2016-02-28 10:44:42
389
原创 LeetCode题解：Path Sum
Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.For example: Given the below binary tree and sum = 2
2016-02-28 10:30:28
338
原创 LeetCode题解：Palindrome Number
Determine whether an integer is a palindrome. Do this without extra space.click to show spoilers.Some hints: Could negative integers be palindromes? (ie, -1)If you are thinking of converting the integ
2016-02-28 10:13:40
388
原创 LeetCode题解：Pascal's Triangle II
Given an index k, return the kth row of the Pascal’s triangle.For example, given k = 3, Return [1,3,3,1].Note: Could you optimize your algorithm to use only O(k) extra space?题意：给定k，返回Pascal 三角形的第k行，要
2016-02-28 10:08:13
572
原创 LeetCode题解：Binary Tree Level Order Traversal
Given a binary tree, return the level order traversal of its nodes’ values. (ie, from left to right, level by level).题意：层序遍历思路：……代码：/** * Definition for a binary tree node. * public class TreeNode {
2016-02-28 10:05:56
333
原创 LeetCode题解：Remove Element
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.题意：给定一个数组与
2016-02-28 09:55:07
427
原创 LeetCode题解：Merge Two Sorted Lists
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.题意：将两个有序链表合并得到一个新的有序链表思路：……代码：/** * Definition for singly-l
2016-02-28 09:26:18
651
原创 LeetCode题解：Power of Three
Given an integer, write a function to determine if it is a power of three.Follow up: Could you do it without using any loop / recursion?题意 ：给定整数，判断是否为3的幂解题思路：纯计算……代码：public boolean isPowerOfThree(int
2016-02-28 09:19:43
374
原创 LeetCode题解：Ugly Number
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
2016-02-28 09:11:30
344
原创 LeetCode题解：Odd Even Linked List
Given a singly linked list, group all odd nodes together followed by the even nodes. Please note here we are talking about the node number and not the value in the nodes.You should try to do it in plac
2016-02-27 20:22:20
536
原创 LeetCode题解：Number of 1 Bits
Write a function that takes an unsigned integer and returns the number of ’1’ bits it has (also known as the Hamming weight).For example, the 32-bit integer ’11’ has binary representation 0000000000000
2016-02-27 20:17:06
468
原创 LeetCode题解：Reverse Linked List
Reverse a singly linked list.题意：反转单链表解题思路：一直取下一个节点作为头部代码：public class Solution { public ListNode reverseList(ListNode head) { return reverseListInt(head,null); } public ListNode reve
2016-02-27 20:12:07
349
原创 LeetCode题解：Excel Sheet Column Number
Related to question Excel Sheet Column TitleGiven a column title as appear in an Excel sheet, return its corresponding column number.For example:A -> 1B -> 2C -> 3...Z -> 26AA -> 27AB -> 28 题意：给
2016-02-27 20:06:59
392
原创 LeetCode题解：Same Tree
Given two binary trees, write a function to check if they are equal or not.Two binary trees are considered equal if they are structurally identical and the nodes have the same value.题意：判断两棵树是否相同解题思路：可以
2016-02-27 20:02:09
253
原创 LeetCode题解：Move Zeroes
Given an array nums, write a function to move all 0’s to the end of it while maintaining the relative order of the non-zero elements.For example, given nums = [0, 1, 0, 3, 12], after calling your funct
2016-02-27 20:00:24
339
原创 LeetCode题解：Maximum Depth of Binary Tree
Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.题意：给定二叉树，找出最大深度思路：DFSpublic class Solution
2016-02-27 19:52:00
297
原创 LeetCode题解：Nim Game
You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3 stones. The one who removes the last stone will be the
2016-02-27 19:42:48
674
原创 LeetCode题解：Linked List Cycle II
Given a linked list, return the node where the cycle begins. If there is no cycle, return null.Note: Do not modify the linked list.Follow up: Can you solve it without using extra space?题意：给定链表，返回环的起点；
2016-02-10 15:56:01
291
原创 LeetCode题解：Linked List Cycle
Given a linked list, determine if it has a cycle in it.Follow up: Can you solve it without using extra space?题意：给定链表，判断是否为环。要求O(1)空间思路：快慢指针，如果存在环，快指针必然遇到慢指针代码：/** * Definition for singly-linked list
2016-02-10 15:22:17
264
空空如也
TA创建的收藏夹 TA关注的收藏夹
TA关注的人