xinqrs01-优快云博客

原创 GPS读书笔记-from2/18/2017-2/21/2017

ch1: introduction卫星数据经射频，中频，adc采样来到数字基带域。卫星导航信号首先经过acquisition(捕获)，tracking(跟踪)，提取帧，提取ephemeris&pseudorange信号，然后计算卫星位置，最后得到user position. 关键是捕获和跟踪。捕获是捕获c/a码的初始相位。跟踪则是跟踪相位，估计频偏，把频偏给补偿到接受信号，提高信噪比。ch2:

2017-02-19 10:13:16 2180 3

原创 (未完成)332. Reconstruct Itinerary

Given a list of airline tickets represented by pairs of departure and arrival airports [from, to], reconstruct the itinerary in order. All of the tickets belong to a man who departs from JFK. Thus, the

2017-02-19 04:16:08 444

原创 331. Verify Preorder Serialization of a Binary Tree

One way to serialize a binary tree is to use pre-order traversal. When we encounter a non-null node, we record the node’s value. If it is a null node, we record using a sentinel value such as #. _9

2017-02-18 09:40:48 450

原创 328. 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

2017-02-18 08:18:27 326

原创 326. 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?s思路: 1. 看是否3的指数，即判断n==3^i。直接的方法就是每次和3求余，如果为０，就除以3,看是否等于１. 2. 但

2017-02-18 07:57:48 265

原创 324. Wiggle Sort II

Given an unsorted array nums, reorder it such that nums[0] < nums[1] > nums[2] < nums[3]….Example: (1) Given nums = [1, 5, 1, 1, 6, 4], one possible answer is [1, 4, 1, 5, 1, 6]. (2) Given nums = [1

2017-02-18 07:31:02 341

原创 322. Coin Change

You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you need to make up that amount. If that amount of money c

2017-02-17 12:56:24 254

原创 319. 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

2017-02-17 10:46:22 258

原创 318. 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

2017-02-17 10:34:09 210

原创 313. Super Ugly Number

Write a program to find the nth super ugly number.Super ugly numbers are positive numbers whose all prime factors are in the given prime list primes of size k. For example, [1, 2, 4, 7, 8, 13, 14, 16,

2017-02-17 09:27:20 333

原创 310. Minimum Height Trees

For a undirected graph with tree characteristics, we can choose any node as the root. The result graph is then a rooted tree. Among all possible rooted trees, those with minimum height are called minim

2017-02-17 07:46:00 254

原创 309. 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

2017-02-15 15:35:37 259

原创 307. Range Sum Query - Mutable

Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.The update(i, val) function modifies nums by updating the element at index i to val. Example: Give

2017-02-15 12:56:32 296

原创 306. Additive Number

Additive number is a string whose digits can form additive sequence.A valid additive sequence should contain at least three numbers. Except for the first two numbers, each subsequent number in the sequ

2017-02-15 10:29:14 246

原创 304. Range Sum Query 2D - Immutable

Given a 2D matrix matrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2, col2). Range Sum Query 2D The above rectangle

2017-02-15 08:20:34 324

原创 303. 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

2017-02-15 07:50:28 256

原创 300. Longest Increasing Subsequence

Given an unsorted array of integers, find the length of longest increasing subsequence.For example, Given [10, 9, 2, 5, 3, 7, 101, 18], The longest increasing subsequence is [2, 3, 7, 101], therefore

2017-02-15 07:32:54 209

原创 299. 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

2017-02-15 05:28:30 346

原创 292. 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

2017-02-15 04:18:37 260

原创 290. 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:

2017-02-15 03:46:29 332

原创 289. Game of Life

According to the Wikipedia’s article: “The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970.”Given a board with m by n ce

2017-02-14 15:19:03 204

原创 287. Find the Duplicate Number

Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, fin

2017-02-14 14:16:08 177

原创 284. Peeking Iterator

Given an Iterator class interface with methods: next() and hasNext(), design and implement a PeekingIterator that support the peek() operation – it essentially peek() at the element that will be return

2017-02-14 13:36:52 200

原创 283. 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

2017-02-14 10:18:57 177

原创 279. Perfect Squares

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

2017-02-14 09:56:49 461

原创 278. 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

2017-02-13 10:31:32 136

原创 275. H-Index II

Follow up for H-Index: What if the citations array is sorted in ascending order? Could you optimize your algorithm?s思路: 1. 排过序的，就更好办了！ 2. 不对，肯定不是o(n)这么便宜的事。排序，又都是正数，还不得用binary search啊。绝了！ 3. debug疑问

2017-02-13 10:16:06 215

原创 274. H-Index

Given 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: “A scien

2017-02-13 09:27:52 271

原创 268. 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

2017-02-13 08:30:50 249

原创 264. Ugly Number II

Write a program to find the n-th ugly number.Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 1, 2, 3, 4, 5, 6, 8, 9, 10, 12 is the sequence of the first 10 ugly

2017-02-13 08:19:52 497

原创 263. 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

2017-02-12 15:13:25 204

原创 260. 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,

2017-02-12 14:57:55 181

原创 258. Add Digits

Given a non-negative integer num, repeatedly add all its digits until the result has only one digit.For example:Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, r

2017-02-12 14:30:00 167

原创 257. Binary Tree Paths

Given a binary tree, return all root-to-leaf paths.For example, given the following binary tree: 1 / \2 3 \ 5All root-to-leaf paths are:[“1->2->5”, “1->3”]s思路： 1. 树。遍历。这道题，dfs最容易，而且是用pre

2017-02-12 13:48:55 180

原创 242. Valid Anagram

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

2017-02-12 12:32:10 168

原创 241. Different Ways to Add Parentheses

Given a string of numbers and operators, return all possible results from computing all the different possible ways to group numbers and operators. The valid operators are +, - and *.Example 1 Input:

2017-02-12 10:34:09 250

原创 240. Search a 2D Matrix II

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:Integers in each row are sorted in ascending from left to right. Integers in each co

2017-02-12 09:07:03 194

原创 238. 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

2017-02-12 08:25:56 171

原创 237. Delete Node in a Linked List

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

2017-02-12 07:15:24 236

原创 235. Lowest Common Ancestor of a Binary Search Tree

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

2017-02-12 07:00:21 940

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