Finding IP Address from hostname in Windows Linux and Unix

 Posted on July 27, 2014  (Last modified on August 7, 2020)  |  5 minutes  |  Kinshuk Chandra

IP Address from hostname in Windows and Linux How many times in a day you have a hostname and you want to know the IP address? Host name to IP address and IP address to hostname conversion is one of frequent thing which we need to do for many things when dealing with networking command in unix. For one command we need IP address for other we need hostname even from bash script some time we require hostname and some time we look for IP address. [Read More]
kodeknight 

Skiplist vs Binary tree

 Posted on July 25, 2014  (Last modified on August 7, 2020)  |  2 minutes  |  Kinshuk Chandra

Here are some of the differences Skiplist Binary tree Concurrency - Skip lists are more amenable to concurrent access/modification. Inserting a node into a skip list is far more localized, only nodes directly linked to the affected node need to be locked. pressure. The most frequently used implementation of a binary search tree is a red-black tree. The concurrent problems come in when the tree is modified it often needs to rebalance. [Read More]
differences  kodeknight  linux  unix  skip-list 

Skiplists

 Posted on July 25, 2014  (Last modified on August 7, 2020)  |  6 minutes  |  Kinshuk Chandra

Goal To understand skiplist. Definition Skiplist is a dynamic search structure, as it is dynamic when it comes to insertion and deletion, which supports search). Other dynamic search structure: Treaps Red black tree B-Trees (2-3 trees etc) Operations on skiplist Search - O(log n) Insert - O(log n) Delete - O(log n) These operations are with high probability, 1/polynomial depending on polynomial number of operation. [Read More]
kodeknight  incomplete  Data Structure  linux  unix  concurrency  skip-list 

Find max subsquare whose border values are all 1

 Posted on July 24, 2014  (Last modified on August 7, 2020)  |  2 minutes  |  Kinshuk Chandra

Problem Imagine you have a square matrix, where each cell is filled with either black or white. Design an algorithm to find the maximum subsquare such that all four borders are filled with black pixels. Solution We are going to scan column by column, checking to see if this column can be the left-border of the desired subsquare. Along each column, we build “sliding windows”, from large size to small size. [Read More]
kodeknight  hard  incomplete  CrackingTheCodingInterview 

Transform one word into another by changing only one letter at a time

 Posted on July 24, 2014  (Last modified on August 7, 2020)  |  2 minutes  |  Kinshuk Chandra

Problem Given two words of equal length that are in a dictionary, write a method to transform one word into another word by changing only one letter at a time. The new word you get in each step must be in the dictionary. EXAMPLE Input: DAMP, LIKE Output: DAMP -> LAMP -> LIMP -> LIME -> LIKE Solution Try thinking this problem in terms of graphs: Consider all words in a dictionary as vertices, and insert an edge between each two vertices that differ by only one letter. [Read More]
Graph  kodeknight  shortest-path  hard  BFS  CrackingTheCodingInterview 

Search a long string for small strings in an array

 Posted on July 23, 2014  (Last modified on August 7, 2020)  |  2 minutes  |  Kinshuk Chandra

Problem Given a string s and an array of smaller strings T, design a method to search s for each small string in T. Solution Method 1 - Using suffix tree We can first get all the suffices of s and check for each element t in T to see if t is the beginning part of any suffices. To make this more efficient, we can build a suffix tree and do the operations. [Read More]
StringAlgo  kodeknight  suffix tree  hard  pattern matching  CrackingTheCodingInterview