Introduction
Dear Readers, upon lot of requests, I have decided to write this new series of posts. This is the first look of a book which I am writing and I would like to share my knowledge and understanding of Spring Framework and its hacks. This series will be available under the J2EE category under the heading "Spring Beginners to Professionals".
As of the time of writing this book and series, the GA version of Spring was 4.2.5, for the new versions few things might vary but more or less concepts and usages will be similar.
This is a series and it would make a lot of sense if read i...

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## Preserve indices while sorting array

Introduction
This is a request from one of the readers. This is mostly useful in competitive programming where you want to sort an array by the values, but at the same time the requirement is to preserve the index of each element.
If I have to explain using an example, then consider the array below. The array is zero indexed.
The first two rows represent the input array and indices of each element in the array. The next two rows represent the sorted array, but the moment you sort it, the index for each element changes. Earlier A was at index 4 but in the sorted array it is at index ...

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## Solving 0/1 Knapsack problem using Dynamic Programming

Introduction
A knapsack is a bag with straps, usually carried by soldiers to help them take their valuables or things which they might need during their journey. The 0/1 knapsack problem is a very famous interview problem. The problem statement is as follows:
Given a set of items, each of which is associated with some weight and value. Find the subset of items which can be carried into the knapsack with weight limit W. It is required that the cumulative value of the items in the knapsack is maximum value possible.
In simple words, it asks you to pick certain items from the set of items ...

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## Solving 0/1 Knapsack problem using Recursion

Introduction
A knapsack is a bag with straps, usually carried by soldiers to help them take their valuables or things which they might need during their journey. The 0/1 knapsack problem is a very famous interview problem. The problem statement is as follows:
Given a set of items, each of which is associated with some weight and value. Find the subset of items which can be carried in a knapsack of capacity W (where W is the weight). It is required that the cumulative value of the items in the knapsack is maximum value possible.
In simple words, it asks you to pick certain items from the...

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## Find Interleaving Strings using Dynamic Programming

Introduction
This problem is already discussed in the post here. This post attempts to solve the same using the dynamic programming approach. Here is a brief description of the problem. Given three strings A, B and C such that A is "ab", B is "ade" and C is "adabe" find if C is an interleaving of A and B or not.
Interleaving means constructing the third string C using the characters of A and B such that the characters in A and B preserve their relative ordering in C. In the above example C is an interleaving of A and B.
Approach to Find Interleaving Strings using Dynamic Programming
How ...

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