More elegant way to check for duplicates in C++ array?

by

You could sort the array in O(nlog(n)), then simply look until the next number. That is substantially faster than your O(n^2) existing algorithm. The code is also a lot cleaner. Your code also doesn’t ensure no duplicates were inserted when they were re-entered. You need to prevent duplicates from existing in the first place.

std::sort(userNumbers.begin(), userNumbers.end());
for(int i = 0; i < userNumbers.size() - 1; i++) {
    if (userNumbers[i] == userNumbers[i + 1]) {
        userNumbers.erase(userNumbers.begin() + i);
        i--;
    }
}

I also second the reccomendation to use a std::set – no duplicates there.

More Related Contents:

  1. sizeof works unusual at c++ after array creation [duplicate]
  2. Why is sizeof giving incorrect number of bytes in C++?
  3. How do I compare chars (or strings) using void functions, also comparing chars that were taken from a struct array
  4. C++ – Find numbers between first and last negative numbers in Array
  5. If statement – C++
  6. Accessing an array out of bounds gives no error, why?
  7. Passing a 2D array to a C++ function
  8. How to convert vector to array
  9. Is std::vector so much slower than plain arrays?
  10. Why does cout print char arrays differently from other arrays?
  11. Address of an array
  12. Why does pointer decay take priority over a deduced template?
  13. Sort a 2D array in C++ using built in functions(or any other method)?
  14. How to initialize std::array elegantly if T is not default constructible?
  15. May I take the address of the one-past-the-end element of an array? [duplicate]
  16. How to initialize a vector in C++ [duplicate]
  17. Is there a function to copy an array in C/C++?
  18. How do I initialize a member array with an initializer_list?
  19. How do I best handle dynamic multi-dimensional arrays in C/C++?
  20. Structure of Arrays vs Array of Structures
  21. Range-based for loop on a dynamic array?
  22. Remove an array element and shift the remaining ones
  23. How to initialize 3D array in C++
  24. How can I use an array as map value?
  25. C++ : Creating an array with a size entered by the user
  26. Pass arrays from C/C++ to Fortran and return a calculated array
  27. How to return array from C++ function to Python using ctypes
  28. array of pointers as function parameter
  29. C / C++ How to copy a multidimensional char array without nested loops?
  30. Polymorphism & Pointers to arrays [duplicate]

Leave a Comment