chilakaka-优快云博客

原创找工作小总结

找了一学期工作，零零碎碎刷了两遍leetcode，网上各种C++常见问题，JAVA常见问题，OS常见问题之类的每次面前都看了看，准备了一堆behavioral questioncareer fair投简历的公司：第一批全是一月底在TAMU的CAREER FAIR上投的，虽然我不是TAMU的。。。。。投了之后有后续的有NI, DELL, DENIM GROUP, MATHWORKS面试的公司

2015-04-30 09:38:31 1199

原创 LeetCode - Bitwise AND of Numbers Range

https://leetcode.com/problems/bitwise-and-of-numbers-range/Given a range [m, n] where 0 For example, given the range [5, 7], you should return 4.一开始的时候，我是打算从m到n挨个AND，结果超时了，后来发现既然是AND，那么只需要

2015-04-19 23:07:25 572

原创 LeetCode - Merge k Sorted Lists

https://leetcode.com/problems/merge-k-sorted-lists/Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.优快云坑爹博客，之前明明写过这篇，居然找不到了！之前用JAVA写的代码，现在是用

2015-04-19 00:07:33 360

原创 LeetCode - Valid Parenthesis

https://leetcode.com/problems/valid-parentheses/Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.The brackets must cl

2015-04-18 22:30:35 410

原创 LeetCode - Maxmimum Gap

https://leetcode.com/problems/maximum-gap/Given an unsorted array, find the maximum difference between the successive elements in its sorted form.Try to solve it in linear time/space.Ret

2015-04-16 08:11:51 425

原创 LeetCode - LRU Cache

https://leetcode.com/problems/lru-cache/Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and set.get(key) - Get the

2015-04-16 06:45:20 311

原创 LeetCode - Populating Next Right Pointers in Each Node I && II

Populating Next Right Pointers in Each Node Ihttps://leetcode.com/problems/populating-next-right-pointers-in-each-node/Given a binary tree struct TreeLinkNode { TreeLinkNode *left

2015-04-16 01:11:53 298

原创 LeetCode - Binary Tree Postorder Traversal

https://leetcode.com/problems/binary-tree-postorder-traversal/这道题不用递归的话思路还是挺复杂的，网上有用一个栈的，有用两个栈的，我这里写的是用一个栈的，就是一直有一个pre和current的指针，来记录上一个被加入到结果list或者被进入栈的节点。当pre是current的父节点时，说明pre还没有处理过(postorder)

2015-04-16 00:47:02 357

原创 LeetCode - Binary Tree Maximum Path Sum

https://leetcode.com/problems/binary-tree-maximum-path-sum/这道题可以用递归做，首先，应该有一个全局变量来保存当前遇到的最大path值。对于每个节点而言，经过它的最大path值，应该是左边的最大path加右边的最大path加自己，如果左边或者右边的最大path是负数，那么就不加这一部分。另外，对于这个节点的父节点而言，经过父节点

2015-04-16 00:23:29 358

原创 LeetCode - Palindrome Partitioning I && II

Palindrome Partitioning Ihttps://leetcode.com/problems/palindrome-partitioning/Given a string s, partition s such that every substring of the partition is a palindrome.Return all possibl

2015-04-15 23:33:36 359

原创 Google电面面经总结

1. 上来问了tree里node求和的问题很简单然后follow up 给一个range 求range里的node值的和，不是path sum 是所有节点的求和然后给个range 值在range之内就加进去然后分析不同的树怎么优化2. encoding，把 abcccdaa 这种字符串变为 ab3xcd2xa 这种3. 给一个String的array，问

2015-04-13 01:48:27 3109

原创 LeetCode - Regular Expression Matching

https://leetcode.com/problems/regular-expression-matching/Implement regular expression matching with support for '.' and '*'.'.' Matches any single character.'*' Matches zero or more of the p

2015-04-12 09:07:53 346

原创 LeetCode - Candy

https://leetcode.com/problems/candy/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 require

2015-04-12 03:17:05 410

原创 LeetCode - Recover Binary Search Tree

https://leetcode.com/problems/recover-binary-search-tree/Two elements of a binary search tree (BST) are swapped by mistake.Recover the tree without changing its structure.Note:A solution

2015-04-11 02:16:53 452

原创 LeetCode - N-Queens I && II

N-Queens Ihttps://leetcode.com/problems/n-queens/Given an integer n, return all distinct solutions to the n-queens puzzle.Each solution contains a distinct board configuration of the n-q

2015-04-11 01:25:00 339

原创 LeetCode - Permutations II

https://leetcode.com/problems/permutations-ii/Given a collection of numbers that might contain duplicates, return all possible unique permutations.For example,[1,1,2] have the following un

2015-04-11 00:43:36 322

原创 LeetCode - Permutations

https://leetcode.com/problems/permutations/Given a collection of numbers, return all possible permutations.For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3],

2015-04-11 00:40:14 333

原创 LeetCode - Word Break II

https://leetcode.com/problems/word-break-ii/Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word.Return all suc

2015-04-10 23:53:42 281

原创 LeetCode - Word Break

https://leetcode.com/problems/word-break/Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.For

2015-04-10 04:57:01 318

原创 LeetCode - Dungeon Game

https://leetcode.com/problems/dungeon-game/The demons had captured the princess (P) and imprisoned her in the bottom-right corner of a dungeon. The dungeon consists of M x N rooms laid out in a

2015-04-10 04:23:55 381

原创 LeetCode - Distinct Subsequences

https://leetcode.com/problems/distinct-subsequences/这道题一开始我还想用 two pointers , backtracking来做，后来想这个是算个数，backtracking太复杂了，而且也没想到很明确的做法。后来看tag发现是DP题，分析一下： a b c d a e b ca

2015-04-10 00:43:08 265

原创 LeetCode - Decode Ways

https://leetcode.com/problems/decode-ways/A message containing letters from A-Z is being encoded to numbers using the following mapping:'A' -> 1'B' -> 2...'Z' -> 26Given an encoded m

2015-04-10 00:17:21 216

原创 LeetCode - Edit Distance

https://leetcode.com/problems/edit-distance/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 ha

2015-04-09 23:32:22 238

原创 LeetCode - Generate Parentheses

https://leetcode.com/problems/generate-parentheses/Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, given n = 3, a solution

2015-04-09 23:05:17 263

原创 LeetCode - Interleaving String

https://leetcode.com/problems/interleaving-string/Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.For example,Given:s1 = "aabcc",s2 = "dbbca",When s3 =

2015-04-09 22:47:30 201

原创 LeetCode - Maximum Depth of Binary Tree

https://leetcode.com/problems/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

2015-04-08 01:11:40 358

原创 LeetCode - Validate Binary Search Tree

https://leetcode.com/problems/validate-binary-search-tree/Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of

2015-04-08 00:32:21 310

原创 LeetCode - Longest Palindromic Substring

https://leetcode.com/problems/longest-palindromic-substring/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

2015-04-07 01:47:18 238

原创 LeetCode - Longest Valid Parentheses

https://leetcode.com/problems/longest-valid-parentheses/Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring.

2015-04-07 01:07:21 366

原创 LeetCode - One Edit Distance

https://leetcode.com/problems/one-edit-distance/Given two strings S and T, determine if they are both one edit distance apart.One Edit Distance即是：1. 插入一个字符2. 更改一个字符，如ab->ac所以分情况是：1. 如果两

2015-04-07 00:42:53 238

原创 LeetCode - Read N Characters Given Read4 I && II

https://leetcode.com/problems/read-n-characters-given-read4/The API: int read4(char *buf) reads 4 characters at a time from a file.The return value is the actual number of characters read. F

2015-04-06 23:45:34 361

原创 LeetCode - Restore IP Addresses

https://leetcode.com/problems/restore-ip-addresses/Given a string containing only digits, restore it by returning all possible valid IP address combinations.For example:Given "2552551113

2015-04-04 07:10:19 235

原创 LeetCode - Reverse Words in a String I && II

https://leetcode.com/problems/reverse-words-in-a-string/这道题O(n)的方法很简单，就是遍历字符串，找到一个词就放到list里面，遍历完后把list里面的单词从后往前连起来就行。而且本来我想用JAVA的s.split(" ")函数的，结果leetcode的用例全部都是不规律的，两个单词间N多空格，或者字符串前后都是空格之类的，所以用s

2015-04-04 06:24:36 366

原创 LeetCode - Scramble String

https://leetcode.com/problems/scramble-string/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 represe

2015-04-04 05:17:15 328

原创 LeetCode - Simplify Path

https://leetcode.com/problems/simplify-path/Given an absolute path for a file (Unix-style), simplify it.For example,path = "/home/", => "/home"path = "/a/./b/../../c/", => "/c"clic

2015-04-04 04:45:18 257

原创 LeetCode - Text Justification

https://leetcode.com/problems/text-justification/Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified.

2015-04-04 04:15:28 399

原创 LeetCode - Wildcard Matching

https://leetcode.com/problems/wildcard-matching/Implement wildcard pattern matching with support for '?' and '*'.'?' Matches any single character.'*' Matches any sequence of characters (inclu

2015-04-03 23:55:38 547

原创 LeetCode - ZigZag Conversion

https://leetcode.com/problems/zigzag-conversion/The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed

2015-04-03 22:45:57 202

原创 LeetCode - Merge Two Sorted Lists

https://leetcode.com/problems/merge-two-sorted-lists/这用到的就是merge sort里面的merge函数，只不过这里是在merge list。public class Solution { public ListNode mergeTwoLists(ListNode l1, ListNode l2) { Li

2015-04-03 05:40:46 193

原创 LeetCode - Reverse Linked List II

https://leetcode.com/problems/reverse-linked-list-ii/这道题跟其他reverse node 的题差不多，只要找到需要reverse的node之前的那个node，再把这个node后面的n-m+1个node掉转就行。如果head node也需要被reverse的话，它之前没有node了，所以需要在前面加一个dummy nodepublic

2015-04-03 05:12:11 268

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