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Archive for June, 2012

why hash code is needed in java

June 24, 2012 Comments off
Categories: General

Searching and Sorting

June 16, 2012 Comments off

Time Complexities :

Searching :

Linear Search :

The worst-case time for a Linear Search is always O(N)

Binary Search :

For Binary search the values should be in a sorted manner.

The worst-case time for binary search is proportional to log2 N: the number of times N can be divided in half before there is nothing left. Using big-O notation, this is O(log N)

Don’t use binary search in the sorted Linked List if data

Reason : Binary search relies on being able to access the kth item in a sequence of values in O(1) time. This is possible when the values are stored in an array, but not when they’re stored in a linked list. So binary search using a linked list would usually be much slower than sequential search.

 

Links : http://pages.cs.wisc.edu/~bobh/367/SORTING.html

Categories: Algorithms

Creating a folder with todays date in Linux

June 3, 2012 Comments off
Categories: Linux/Unix

java – NoSuchMethodError: org.slf4j.helpers.MessageFormatter.format

June 3, 2012 Comments off
java.lang.NoSuchMethodError: org.slf4j.helpers.MessageFormatter.format(Ljava/lang/String;Ljava/lang/Object;)Lorg/slf4j/helpers/FormattingTuple; at org.slf4j.impl.JDK14LoggerAdapter.info(JDK14LoggerAdapter.java:304) .......... ........... ............ 

Reason:This kind of errors occurs in 2 cases 
In compatible slf4j version with log4j 
If your class path has multiple slf4j and log4j versions.  

Solution : Below log4j and slf4j combination worked for me. 
log4j-1.2.16.jar 
slf4j-api-1.6.1.jar 
slf4j-log4j12-1.6.4.jar 
Categories: Errors & Exceptions
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