4fd800b3a8 2011-02-23        kinaba: lb = lower_bound(k)
4fd800b3a8 2011-02-23        kinaba:   ... k-1] lb [k ...
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: ub = upper_bound(k)
4fd800b3a8 2011-02-23        kinaba:   .., k] ub [k+1 ...
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: なので任意の開閉区間をイテレータの [) 区間に直すには
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba:   [A, B]
4fd800b3a8 2011-02-23        kinaba:     = [ lower_bound(A), upper_bound(B) )
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba:   [A, B)
4fd800b3a8 2011-02-23        kinaba:     = [ lower_bound(A), lower_bound(B) )
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba:   (A, B]
4fd800b3a8 2011-02-23        kinaba:     = [ upper_bound(A), upper_bound(B) )
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba:   (A, B)
4fd800b3a8 2011-02-23        kinaba:     = [ upper_bound(A), lower_bound(B) )