How to erase duplicate element in vector, efficiently

I have

 vector<string> data ; // I hold some usernames in it

In that vector, I have duplicate element(s), so I want erase this/these element(s).Are there any algorithm or开发者_Python百科 library function to erase duplicate element(s)?

ex :
    In data;
           abba, abraham, edie, Abba, edie
    After operation;
           abba, abraham, edie, Abba

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If you can sort the elements in the container, the straightforward and relatively efficient solution would be:

std::sort(data.begin(), data.end());
data.erase(std::unique(data.begin(), data.end()), data.end());

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I'm not sure there is a really good way to do it. What I would do is sort (in a different array, if you need the original in tact) and then run through it.

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"set" does not allow duplicates. You can use that to filter out duplicates.

1. Create a set
2. Add all usernames to set
3. Create a new vector
4. Add all elements from set to vector

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If you really need to do it efficiently, then should do an in place sort first, and then go through the container by yourself instead of using std::unique, fetch unique items into a new vector, at then end do a swap.

I just checked the source code of std::unique, it will do a lot move when finding one duplicate, move hurts vector's performance.