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原创 <<模式识别与机器学习 (Pattern Recognization and Maching Learning)>>(PRML) 总结

\quadBishop 的大作《模式识别与机器学习》(Pattern Recognization and Maching Learning)，简称为PRML，这本书被认为是贝叶斯方法的扛鼎之作，我有幸忙里偷闲地把这本书通读了一遍并且也把各个章节的习题几乎完成了一遍，可以见我的博客，作为看完这本书最后一个环节，我想为我看完这本书做一个总结。总结分为如下几个部分，分别是阅读此书可以采取的方法，本书主要内

2016-12-29 19:25:22 8370

原创 119：Search a 2D Matrix II

题目：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 ea

2017-03-26 11:46:30 328

原创 118：Search a 2D Matrix

题目：Write an efficient algorithm that searches for a value in an mn matrix. This matrix has the following properties: • Integers in each row are sorted from left to right. • The first integer of eac

2017-03-26 11:39:59 334

原创 117：Search for a Range

题目：Given a sorted array of integers, find the starting and ending position of a given target value. Your algorithm’s runtime complexity must be in the order of O(log n). If the target is not found in

2017-03-26 11:32:00 296

原创 116：Kth Largest Element in an Array

题目：Find the k -th largest element in an unsorted array. For example, given [3,2,1,5,6,4] and k = 2 , return 5. Note: You may assume k is always valid, 1 ≤ k ≤ array’s length.解析1：堆排序，维护一个 k 大小的小根堆，将数组中

2017-03-25 19:55:19 357

原创 115：Largest Number

题目：Given a list of non negative integers, arrange them such that they form the largest number. For example, given [3, 30, 34, 5, 9] , the largest formed number is 9534330 . Note: The result may be ve

2017-03-25 19:45:59 288

原创 114：Sqrt(x)

题目：Implement int sqrt(int x). Compute and return the square root of x.该题目比较简单，可以使用二分法，代码如下：// 二分查找// 时间复杂度 O(logn)，空间复杂度 O(1)class Solution {public: int mySqrt(int x) { int l

2017-03-25 19:41:02 250

原创 113：Pow(x,n)

题目：Implement pow(x, n).解析1：使用递归法，因为xn=(x2)n/2∗xn%2 x^n = (x^2)^{n / 2} * x^{n\%2}，代码如下：// 递归法，时间复杂度 O(logn)// 注意：-5 / 2 = -2, -5 % 2 = -1;class Solution {public: double myPow(double x, int n

2017-03-25 19:39:09 237

原创 112：Maximum Gap

题目：Given an unsorted array, find the maximum difference between the successive elements in its sorted form. Try to solve it in linear time/space. Return 0 if the array contains less than 2 elements.

2017-03-25 19:33:20 273

原创 111：H-Index

题目：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

2017-03-25 19:30:21 431

原创 110：Sort Colors

题目：Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue. Here, we will use the integers

2017-03-25 19:21:34 218

原创 109：First Missing Positive

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 constant spa

2017-03-25 19:16:25 220

原创 108：Sort List

题目：Sort a linked list in O(nlogn) time using constant space complexity。解析：可以使用归并排序算法，将链表从中间分开，然后将这中间分开的两段链表分别排序，再合并。时间复杂度为 O(nlogn)class Solution {public: ListNode* sortList(ListNode* head) {

2017-03-25 19:11:51 204

原创 107：Insertion Sort List

题目：Sort a linked list using insertion sort代码如下：// 时间复杂度 O(n^2)，空间复杂度 O(1)class Solution {public: ListNode* insertionSortList(ListNode* head) { if (!head) return head;

2017-03-25 19:06:34 231

原创 106：Merge k Sorted Lists

题目：Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.解析1：反复调用 merge two sorted lists 函数，假设每条链平均长度为 n，则时间复杂度为 O(2n + 3n + … + kn) = O(nk^2)，代码如下：class Sol

2017-03-25 19:03:12 249

原创 105：Merge Sorted Array

题目：Given two sorted integer arrays A and B, merge B into A as one sorted array. Note: You may assume that A has enough space to hold additional elements from B. The number of elements initialized in A

2017-03-25 18:54:50 220

原创 104：Factorial Trailing Zeroes

题目：Given an integer n , return the number of trailing zeroes in n! . Note: Your solution should be in logarithmic time complexity.解析：计算阶层尾0数目的公式为 N = n / 5 + n / 5^2 + n / 5^3 + …代码如下：/ 时间复杂度 O(log n)

2017-03-19 13:42:33 270

原创 103：Fraction to Recurring Decimal

题目：Given two integers representing the numerator and denominator of a fraction, return the fraction in string format. If the fractional part is repeating, enclose the repeating part in parentheses.

2017-03-19 13:40:24 281

原创 103：Fraction to Recurring Decimal

题目：Given two integers representing the numerator and denominator of a fraction, return the fraction in string format. If the fractional part is repeating, enclose the repeating part in parentheses.

2017-03-19 00:13:38 228

原创 102：Super Ugly Number

题目：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, 1

2017-03-16 23:07:42 219

原创 101：Ugly Number II

题目：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 u

2017-03-16 23:05:19 234

原创 100：Ugly Number

题目：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

2017-03-16 23:00:24 171

原创 99：Happy Number

题目：Write an algorithm to determine if a number is “happy”.A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares o

2017-03-16 22:58:09 191

原创 98：Maximal Rectangle

题目：Given a 2D binary matrix filled with 0’s and 1’s, find the largest rectangle containing all ones 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

2017-03-15 23:30:25 171

原创 97：Maximal Square

题目：Given a 2D binary matrix filled with 0’s and 1’s, find the largest square containing only 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

2017-03-15 23:14:33 200

原创 96：Palindrome Partitioning II

题目：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

2017-03-14 23:35:15 228

原创 95：Palindrome Partitioning

题目：Given a string s, partition s such that every substring of the partition is a palindrome. Return all possible palindrome partitioning of s. For example, given s = “aab”, Return [ [“aa”,”b”], [“

2017-03-14 23:31:03 160

原创 94：Maximum Subarray

题目：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

2017-03-13 23:22:23 171

原创 93：Triangle

题目：Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below. For example, given the following triangle [ [2], [3,4], [6,5,7], [

2017-03-13 23:15:35 183

原创 92：Container With Most Water

题目：Given n non-negative integers a1; a2; :::; an, where each represents a point at coordinate (i; ai). n vertical lines are drawn such that the two endpoints of line i is at (i; ai) and (i; 0). Find t

2017-03-13 08:35:23 226

原创 91：Longest Substring Without Repeating Characters

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 3. F

2017-03-12 23:15:18 214

原创 90：Best Time to Buy and Sell Stock II

题目：Say you have an array for which the i-th 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

2017-03-12 23:10:05 216

原创 89：Best Time to Buy and Sell Stock

题目：Say you have an array for which the i-th element is the price of a given stock on day i. If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock

2017-03-12 23:08:24 182

原创 88：Jump Game II

题目：Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position. Your goal is

2017-03-12 14:56:35 190

原创 87 ：Jump Game

题目：Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position. Determine if yo

2017-03-12 14:54:38 186

原创 86：Sqrt(x)

题目：Implement int sqrt(int x). Compute and return the square root of x.解题代码如下：下面代码的思想及编写参考了网址https://github.com/soulmachine/leetcode#leetcode题解题目// 二分查找// 时间复杂度 O(logn)，空间复杂度 O(1)class Solution {pub

2017-03-11 22:03:26 198

原创 85：Pow(x,n)

题目：Implement pow(x, n).该题有递归和迭代两种解法解析1：递归方法，代码如下：// 递归法，时间复杂度 O(logn)// 注意：-5 / 2 = -2, -5 % 2 = -1;class Solution {public: double myPow(double x, int n) { if (n < 0) return

2017-03-11 22:01:50 227

原创 84：Sum Root to Leaf Numbers

题目：Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf path 1->2->3 which represents the number 123. Find the total su

2017-03-10 23:52:15 235

原创 83：Populating Next Right Pointers in Each Node

题目：见https://leetcode.com/problems/populating-next-right-pointers-in-each-node/?tab=Description解析1：由于该题目要求使用常数空间，因此只能使用迭代法，代码如下，注意代码也能适用该问题的第二个版本https://leetcode.com/problems/populating-next-right-point

2017-03-10 23:15:59 156

原创 82：Binary Tree Maximum Path Sum

题目：Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. For example: Given the below binary tree, 1 / \ 2 3 Return 6.下面代码的思想及编写参考了网址https://github.co

2017-03-10 22:40:47 120

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