neverlandly - 博客园

2015年12月17日

摘要： Analysis: if the last one is not robbed, then you are free to choose whether to rob the first one. you can break the circle by assuming the first hous 阅读全文

posted @ 2015-12-17 12:20 neverlandly 阅读(337) 评论(0) 推荐(0)

Leetcode: Contains Duplicate II

摘要： Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the ... 阅读全文

posted @ 2015-12-17 07:44 neverlandly 阅读(198) 评论(0) 推荐(0)

Leetcode: Kth Largest Element in an Array

摘要： 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 examp... 阅读全文

posted @ 2015-12-17 07:30 neverlandly 阅读(347) 评论(0) 推荐(0)

Leetcode: Contains Duplicate

摘要： Use HashSet: 阅读全文

posted @ 2015-12-17 07:01 neverlandly 阅读(198) 评论(0) 推荐(0)

Leetcode: Minimum Size Subarray Sum

摘要： Haven't think about the O(nlogn) solution. O(n) solution is to maintain a window My solution: shrink as much as possible while maintaining the window 阅读全文

posted @ 2015-12-17 06:52 neverlandly 阅读(289) 评论(0) 推荐(0)

Leetcode: Add and Search Word - Data structure design

摘要：方法1：brute force: search function compares each word with the pattern, time complexity: O(nk), n is number of words in dictionary, k is averge length 方阅读全文

posted @ 2015-12-17 06:46 neverlandly 阅读(619) 评论(0) 推荐(0)

2015年12月16日

Leetcode: Implement Trie (Prefix Tree) && Summary: Trie

摘要：参考百度百科：Trie树 a trie, also called digital tree and sometimes radix tree or prefix tree (as they can be searched by prefixes) The time complexity to ins 阅读全文

posted @ 2015-12-16 13:45 neverlandly 阅读(529) 评论(0) 推荐(0)

Leetcode: Course Schedule II

摘要： 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 t 阅读全文

posted @ 2015-12-16 12:25 neverlandly 阅读(325) 评论(0) 推荐(0)

Leetcode: Course Schedule

摘要： The hint provided by leetcode is: Hints: BFS: 典型的拓扑排序。原理也很简单，在一个有向图中，每次找到一个没有前驱节点的节点（也就是入度为0的节点），然后把它指向其他节点的边都去掉，重复这个过程（BFS），直到所有节点已被找到，或者没有符合条件的节点（如果阅读全文

posted @ 2015-12-16 11:18 neverlandly 阅读(311) 评论(0) 推荐(0)

2015年12月15日

Leetcode: Isomorphic Strings

摘要： Best: O(N) time, constant space 复杂度时间 O(N) 空间 O(N) 思路用一个哈希表记录字符串s中字母到字符串t中字母的映射关系，一个集合记录已经映射过的字母。或者用两个哈希表记录双向的映射关系。这里不能只用一个哈希表，因为要排除egg->ddd这种多对一的映射阅读全文

posted @ 2015-12-15 11:46 neverlandly 阅读(333) 评论(0) 推荐(0)

Leetcode: Reverse Linked List

摘要：基本迭代 Time: O(N), Space: O(1) 基本递归 Time: O(N), Space: O(N)递归栈大小阅读全文

posted @ 2015-12-15 11:15 neverlandly 阅读(267) 评论(0) 推荐(0)

Leetcode: Count Primes

摘要： Count the number of prime numbers less than a non-negative number, n.Algorithm: The sieve of Eratosthenes,Referring to Summary: Primes0 and 1 are not ... 阅读全文

posted @ 2015-12-15 03:09 neverlandly 阅读(276) 评论(0) 推荐(0)

Leetcode: Remove Linked List Elements

摘要： set Dummy node 这题有个重要的follow up，就是在一个环里怎么删除节点：参考：http://www.cnblogs.com/EdwardLiu/p/5975748.html 阅读全文

posted @ 2015-12-15 02:24 neverlandly 阅读(268) 评论(0) 推荐(0)

Leetcode: Bitwise AND of Numbers Range

摘要： Given a range [m, n] where 0 maxRange) continue; 9 int mi = (m>>i) & 1;10 int ni = (n>>i) & 1;11 if (mi == 1 && n... 阅读全文

posted @ 2015-12-15 02:14 neverlandly 阅读(217) 评论(0) 推荐(0)

Leetcode: Happy Number

摘要： 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 intege 阅读全文

posted @ 2015-12-15 00:53 neverlandly 阅读(315) 评论(0) 推荐(0)

2015年9月2日

Latex技巧

posted @ 2015-09-02 09:44 neverlandly 阅读(350) 评论(0) 推荐(0)

2015年4月21日

Lintcode: Singleton && Summary: Synchronization and OOD

摘要： Singleton is a most widely used design pattern. If a class has and only has one instance at every moment, we call this design as singleton. For exampl... 阅读全文

posted @ 2015-04-21 04:28 neverlandly 阅读(1829) 评论(0) 推荐(1)

2015年4月16日

Lintcode: Topological Sorting

摘要：这道题参考了网上一些很好的思路： method1: Record the pre nodes of every node, then find out a node without pre node in each iteration and delete this node from unvisi 阅读全文

posted @ 2015-04-16 12:29 neverlandly 阅读(1054) 评论(0) 推荐(0)

2015年4月15日

Lintcode: Rotate String

摘要： Given a string and an offset, rotate string by offset. (rotate from left to right)ExampleGiven "abcdefg"for offset=0, return "abcdefg"for offset=1, re... 阅读全文

posted @ 2015-04-15 05:44 neverlandly 阅读(1458) 评论(0) 推荐(0)

Lintcode: Two Strings Are Anagrams

摘要： Write a method anagram(s,t) to decide if two strings are anagrams or not.ExampleGiven s="abcd", t="dcab", return trueO(N)time, O(1) space 1 public cla... 阅读全文

posted @ 2015-04-15 04:08 neverlandly 阅读(950) 评论(0) 推荐(0)

2015年4月12日

Leetcode: House Robber

摘要： This particular problem and most of others can be approached using the following sequence: https://leetcode.com/problems/house-robber/discuss/156523/F 阅读全文

posted @ 2015-04-12 03:36 neverlandly 阅读(590) 评论(0) 推荐(0)

2015年4月11日

Leetcode: Binary Tree Right Side View

摘要：这道题就是BT的Level Order Traversal，每次要换一层的时候，记录当前节点注意，每次都是先添加右边child，所以是i==0的时候add 阅读全文

posted @ 2015-04-11 07:06 neverlandly 阅读(789) 评论(0) 推荐(0)

Leetcode: Number of Islands

摘要： DFS的Flood Fill方法，不使用额外visited数组，但是用‘1’变成‘2’表示visited的方法复杂度时间 O(NM) 空间 O(max(N,M)) 递归栈空间 Union Find: (Quick Union) follow up是找最大岛的面积，想法是设置两个全局变量 max 阅读全文

posted @ 2015-04-11 05:20 neverlandly 阅读(2351) 评论(0) 推荐(0)

2015年4月6日

Lintcode: Subarray Sum

摘要： Given an integer array, find a subarray where the sum of numbers is zero. Your code should return the index of the first number and the index of the l... 阅读全文

posted @ 2015-04-06 12:48 neverlandly 阅读(640) 评论(1) 推荐(0)

Lintcode: Sort Letters by Case

摘要： Given a string which contains only letters. Sort it by lower case first and upper case second.NoteIt's not necessary to keep the original order of low... 阅读全文

posted @ 2015-04-06 09:31 neverlandly 阅读(1086) 评论(0) 推荐(0)

Lintcode: Sort Colors II

摘要： Given an array of n objects with k different colors (numbered from 1 to k), sort them so that objects of the same color are adjacent, with the colors ... 阅读全文

posted @ 2015-04-06 09:11 neverlandly 阅读(706) 评论(0) 推荐(0)

2015年4月4日

Lintcode: Single Number III

摘要： Given 2*n + 2 numbers, every numbers occurs twice except two, find them.ExampleGiven [1,2,2,3,4,4,5,3] return 1 and 5ChallengeO(n) time, O(1) extra sp... 阅读全文

posted @ 2015-04-04 04:59 neverlandly 阅读(2521) 评论(0) 推荐(0)

Lintcode: Search Range in Binary Search Tree

摘要： Given two values k1 and k2 (where k1 k1, 如果否，则不需要继续向左递归；右子树的处理方法类似第一次做法，把result数组作为return type，不好，消耗额外空间 1 public class Solution { 2 /** 3 *... 阅读全文

posted @ 2015-04-04 03:39 neverlandly 阅读(1229) 评论(0) 推荐(0)

Lintcode: Binary Tree Serialization (Serialization and Deserialization Of Binary Tree)

摘要： Design an algorithm and write code to serialize and deserialize a binary tree. Writing the tree to a file is called 'serialization' and reading back f... 阅读全文

posted @ 2015-04-04 02:59 neverlandly 阅读(1005) 评论(0) 推荐(0)

2015年4月2日

Lintcode: Search a 2D matrix II

摘要： Write an efficient algorithm that searches for a value in an m x n matrix, return the occurrence of it.This matrix has the following properties: * ... 阅读全文

posted @ 2015-04-02 12:26 neverlandly 阅读(2222) 评论(0) 推荐(0)

Lintcode: Rehashing

摘要： The size of the hash table is not determinate at the very beginning. If the total size of keys is too large (e.g. size >= capacity / 10), we should do... 阅读全文

posted @ 2015-04-02 11:13 neverlandly 阅读(850) 评论(0) 推荐(0)

Lintcode: Recover Rotated Sorted Array

摘要： Given a rotated sorted array, recover it to sorted array in-place.Example[4, 5, 1, 2, 3] -> [1, 2, 3, 4, 5]ChallengeIn-place, O(1) extra space and O(n... 阅读全文

posted @ 2015-04-02 10:33 neverlandly 阅读(1366) 评论(0) 推荐(0)

Lintcode: Product of Array Exclude Itself

摘要： Given an integers array A.Define B[i] = A[0] * ... * A[i-1] * A[i+1] * ... * A[n-1], calculate B without divide operation.ExampleFor A=[1, 2, 3], B is... 阅读全文

posted @ 2015-04-02 09:59 neverlandly 阅读(1932) 评论(0) 推荐(0)

Lintcode: Previous Permuation

摘要： Given a list of integers, which denote a permutation.Find the previous permutation in ascending order.NoteThe list may contains duplicate integers.Exa... 阅读全文

posted @ 2015-04-02 07:01 neverlandly 阅读(1212) 评论(0) 推荐(0)

Lintcode: Partition Array

摘要： Given an array "nums" of integers and an int "k", Partition the array (i.e move the elements in "nums") such that, * All elements = k are moved to ... 阅读全文

posted @ 2015-04-02 06:21 neverlandly 阅读(1702) 评论(0) 推荐(0)

Lintcode: O(1) Check Power of 2

摘要： Using O(1) time to check whether an integer n is a power of 2.ExampleFor n=4, return trueFor n=5, return falseChallengeO(1) timeTags Expand 这道题考察bit m... 阅读全文

posted @ 2015-04-02 05:24 neverlandly 阅读(575) 评论(0) 推荐(0)

Lintcode: Minimum Adjustment Cost

摘要： 1 Given an integer array, adjust each integers so that the difference of every adjcent integers are not greater than a given number target.2 3 If the ... 阅读全文

posted @ 2015-04-02 04:56 neverlandly 阅读(1961) 评论(0) 推荐(0)

Lintcode: Nth to Last Node in List

摘要： Find the nth to last element of a singly linked list. The minimum number of nodes in list is n.ExampleGiven a List 3->2->1->5->null and n = 2, return... 阅读全文

posted @ 2015-04-02 03:40 neverlandly 阅读(553) 评论(0) 推荐(1)

2015年4月1日

Summary: Trie Data Structure

摘要： Implement a Trie Data Structure, and search() & insert() function: we need to implement both Class Trie and Class TrieNode Class Trie: Class TrieNode: 阅读全文

posted @ 2015-04-01 11:29 neverlandly 阅读(369) 评论(0) 推荐(0)

2015年3月22日

CareerCup: 17.14 minimize unrecognized characters

摘要： Oh, no! You have just completed a lengthy document when you have an unfortu-nate Find/Replace mishap. You have accidentally removed all spaces, p... 阅读全文

posted @ 2015-03-22 11:55 neverlandly 阅读(749) 评论(0) 推荐(0)