What's the Most Efficient Way to Remove Duplicates and Sort a C Vector?

Efficiently Erasing Duplicates and Sorting a Vector

To eliminate duplicates and sort a C vector effectively, consider the following approaches:

• std::unique and std::sort:

  • This method iterates through the vector, removing duplicates with std::unique, and then sorts the elements with std::sort. However, this approach is not efficient for large vectors with many duplicates.

• std::set:

  • An alternative is to convert the vector to a std::set, which automatically removes duplicates. You can then assign the sorted elements back to the vector. This method can be faster when there are numerous duplicates.

• Comparison of Approaches:

  • Benchmarks show that converting to a set is more efficient for large vectors with high duplicate counts than using std::unique and std::sort directly.

Additional Considerations:

• Order of Operations: Sorting before using std::unique will not guarantee a sorted result afterward.
• Multiple Criteria: If you need to sort by multiple criteria, consider using std::sort and a lambda function for custom comparison.

In summary, the most efficient way to erase duplicates and sort a vector depends on the size and density of duplicates within the vector. For vectors with numerous duplicates, converting to a std::set offers superior performance.

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