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601. Flatten 2D Vector Implement an iterator to flatten a 2d vector. Example Given 2d vector = [ [1,2], [3], [4,5,6] ] By calling next repeatedly until hasNext returns false, the order of elements returned by next should be: [1,2,3,4,5,6]. public class Vector2D implements Iterator&
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LintCode-143.Sort Colors II 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 in the order 1, 2, ... k. Notice: You are not suppose to use the library's
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Consistent Hashing II 在 Consistent Hashing I 中我们介绍了一个比较简单的一致性哈希算法，这个简单的版本有两个缺陷： 1. 增加一台机器之后，数据全部从其中一台机器过来，这一台机器的读负载过大，对正常的服务会造成影响。 2. 当增加到3台机器的时候，每台服务器的负载量不均衡，为1:1:2。 为了解决这个问题，引入了 micro-shards 的概念，一个更好的算法是这样： 1. 将 360° 的区间分得更细。从 0~359 变为一个 0 ~ n-1 的区间，将这个区间首尾相接，连成一个圆。 2. 当加入一台新的机器的时候，随机选择在圆周中撒 k 个点，代表这台机器的 k 个 micro-shards。 3. 每个数据在圆周上也对应一个点，这个点通过一个
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Consistent Hashing 一般的数据库进行horizontal shard的方法是指，把 id 对 数据库服务器总数 n 取模，然后来得到他在哪台机器上。这种方法的缺点是，当数据继续增加，我们需要增加数据库服务器，将 n 变为 n+1 时，几乎所有的数据都要移动，这就造成了不 consistent。为了减少这种 naive 的 hash方法(%n) 带来的缺陷，出现了一种新的hash算法：一致性哈希的算法——Consistent Hashing。这种算法有很多种实现方式，这里我们来实现一种简单的 Consistent Hashing。 1. 将 id 对 360 取模，假如一开始有3台机器，那么让3台机器分别负责0~119, 120~239, 240~359
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LintCode-127.Topological Sorting Given an directed graph, a topological order of the graph nodes is defined as follow: For each directed edge A -> B in graph, A must before B in the order list. The first node in the order can be any node in the graph with
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LintCode-14.First Position of Target For a given sorted array (ascending order) and a target number, find the first index of this number in O(log n) time complexity. If the target number does not exist in the array, return -1. Example If the array is [1, 2, 3, 3,
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LintCode-160.Find Minimum in Rotated Sorted Array II Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). Find the minimum element. Notice The array may contain duplicates. Example
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LintCode-217.Remove Duplicates from Unsorted List Write code to remove duplicates from an unsorted linked list. Example Given 1->3->2->1->4. Return 1->3->2->4 Challenge (hard) How would you solve this problem if a temporary buffer is not allowed?
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LintCode-133.Longest Words Given a dictionary, find all of the longest words in the dictionary. Example Given { "dog", "google", "facebook", "internationalization", "blabla" } the longest words are(is) ["internationalization"]. Given { "like", "love", "hate"
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LintCode-170.Rotate List Given a list, rotate the list to the right by k places, where k is non-negative. Example Given 1->2->3->4->5 and k = 2, return 4->5->1->2->3. /** * Definition for singly-linked list. * public class ListNode
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LintCode-109. Triangle Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below. Notice Bonus point if you are able to do this using only O(n) extra space, where n is the total number of rows
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LintCode-111.Climbing Stairs You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top? Example Given an example n=3 , 1+1+1=2+1=
