Three Way Quick Sort - Coursera Algorithms

Three Way Quick Sort uses multiple partition elements, such that the there are no larger entries to their left and no smaller entries to their right. It is in place, but not a stable sort. This is used to deal with duplicate elements.

Time complexity: O(NlgN)


Following is the program, partition elements are from lt to gt:

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Quick Select - Coursera Algorithms

Quick select finds k^th smallest element by partitioning. It takes linear time and O(N²) in worst case.

Following is the program:

Quick Sort - Coursera Algorithms

Quick Sort uses a partition element, such that the there are no larger entries to it's left and no smaller entries to it's right. It is in place, but not a stable sort.

Time complexity: O(NlgN)
Worst case : O(N²)

Following is the program: