<algorithm>

swap()

template <class T> void swap ( T& a, T& b )
{
  T c(a); a=b; b=c;
}

reverse()

template <class BidirectionalIterator>
  void reverse (BidirectionalIterator first, BidirectionalIterator last)
{
  while ((first!=last)&&(first!=--last)) {
    std::iter_swap (first,last);
    ++first;
  }
}

sort()

template <class RandomAccessIterator, class Compare>
  void sort (RandomAccessIterator first, RandomAccessIterator last, Compare comp);

bool bigger(student a, student b)
{
    return (a.score > b.score);
}
struct student{
    string name;
    char gender;
    int score;
    };   
vector<student> v;
sort(v.begin(), v.end(), bigger);

unique()

从输入序列中“删除”所有相邻的重复元素，并将这些元素移到最后，返回一个迭代器指针，指针指向的正是最后那些重复元素的第一个元素

prev_permutation()/next_permutation()

template bool prev_permutation (BidirectionalIterator first, BidirectionalIterator last );
parameters: 
    first, last : Bidirectional iterators to the initial and final positions of the sequence. The range 
    used is [first, last), which contains all the
    elements between first and last, including 
    the element pointed by first but not the element
    pointed by last.
return value: 
    true : if the function could rearrange 
        the object as a lexicographicaly smaller permutation.
    Otherwise, the function returns false to indicate that 
        the arrangement is not less than the previous, but the largest possible (sorted in descending order).