C++ Vector STL stuff

• std::vector stuff

  • sort a vector

    #include <functional.h> //for greater<int>( )
    #include <vector>
    #include <algorithm>
        
    std::vector<int> arr{1,12,-3,7,5};
        
    std::begin(arr.begin(), arr.end());
    std::begin(arr.begin(), arr.end(), greater<int>());
        
    

    • The std::greater is a functional object which is used for performing comparisons. It is defined as a Function object class for the greater-than inequality comparison. Alternatively, you can use greater<int>( ) with C styled arrays too

      int arr[] = {1,12,-3,7,5};
      sort(arr, arr + 9, greater<int>());
      

  • slice a vector

    template <typename T>
    vector<T> slicing(vector<T> const& v,
                      int X, int Y)
    {
          
        // Begin and End iterator
        auto first = v.begin() + X;
        auto last = v.begin() + Y + 1;
          
        // Copy the element
        vector<T> vector(first, last);
          
        // Return the results
        return vector;
    }
    

• Remove duplicate elements

  ```c++ vec.resize(std::distance(vec.begin(), std::unique(vec.begin(), vec.end())));

• Remove duplicate elements from vector std::unique(begin, end) returns an iterator to the position of the vector after which, the vector contains duplicate elements

          nums.erase(unique(nums.begin(),nums.end()),nums.end());