iterator lower_bound( const Key& key );  (1)  
const_iterator lower_bound( const Key& key ) const;  (1)  
template< class K > iterator lower_bound(const K& x);  (2)  (since C++14) 
template< class K > const_iterator lower_bound(const K& x) const;  (2)  (since C++14) 
key
.x
. This overload only participates in overload resolution if the qualifiedid Compare::is_transparent
is valid and denotes a type. They allow calling this function without constructing an instance of Key
.key    key value to compare the elements to 
x    alternative value that can be compared to Key 
Iterator pointing to the first element that is not less than key
. If no such element is found, a pasttheend iterator (see end()
) is returned.
Logarithmic in the size of the container.
returns range of elements matching a specific key (public member function) 

returns an iterator to the first element greater than the given key (public member function) 
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