Introduction to Data Structures & Algorithms in Java

One of the problems that people face in writing algorithms is how to translate their thoughts into a programming language. Many people cannot even start writing the very first statement of an algorithm. I suggest that if you are having such trouble, don't try to solve the whole problem together, rather break it down into smaller, easier parts. For e.g. try doing the following in writing code for the selection sort algorithm -

• First try to write a method, which just finds the minimum number in the data array. Don't think about anything else, just that method. If you write it in a different method, then you may need to pass the data array as a parameter to that method. Return the index of that minimum element from this method.
• Now change the method to find the minimum number STARTING FROM A PARTICULAR INDEX. So you will need to pass this index as a parameter.
• Write another method which can swap items in an array, located at two different indexes. What parameters should be passed to this method?

Hopefully, by this time you will have enough clarity on completing the sorting algorithm, if you understood the pseudo code.

Try to write generic sort methods, like shown in the InsertionSortWithGenerics.java, for Bubble sort and Selection sort algorithms as an exercise. But if you don't want to get into generics at this point, you may choose to skip this section.

This last lecture also contains the complete project file (zipped) in the downloadable materials section.