针对已序区间执行的算法，执行前提是源区间必须在某个排序准则下已序。
搜寻元素(Searching)
1.检查某个元素是否存在
bool
binary_search(ForwardIterator beg,ForwardIterator end,
const T& value)
bool
binary_search(ForwardIterator beg,ForwardIterator end,
const T& value,
BinaryPredicate op)
以下示范binary_search()的用法
1 #include "algostuff.hpp"
2 using namespace std;
3
4 int main()
5 {
6 list<int> coll;
7 INSERT_ELEMENTS(coll,1,9);
8 PRINT_ELEMENTS(coll);
9 if(binary_search(coll.begin(),coll.end(),5))
10 cout<<"5 is present"<<endl;
11 else
12 cout<<"5 is not present"<<endl;
13 if(binary_search(coll.begin(),coll.end(),42))
14 cout<<"42 is present"<<endl;
15 else
16 cout<<"42 is not present"<<endl;
17 }
2.检查若干值是否存在
bool
includes(InputIterator beg,
InputIterator end,
InputIterator searchBeg,
InputIterator searchEnd)
bool
includes(InputIterator beg,
InputIterator end,
InputIterator searchBeg,
InputIterator searchEnd,
BinaryPredicate op)
两种形式都用来判断已序区间[beg,end)是否包含另一已序区间[searchBeg,searchEnd)的全部元素
以下程序示范inlcudes()的用法
1 #include "algostuff.hpp"
2 using namespace std;
3
4 int main()
5 {
6 list<int> coll;
7 vector<int> search;
8 INSERT_ELEMENTS(coll,1,9);
9 PRINT_ELEMENTS(coll,"coll: ");
10 search.push_back(3);
11 search.push_back(4);
12 search.push_back(7);
13 PRINT_ELEMENTS(search,"search: ");
14 if(includes(coll.begin(),coll.end(),search.begin(),search.end()))
15 cout<<"all elements of search are also in coll"<<endl;
16 else
17 cout<<"not all elements of search are also in coll"<<endl;
18 }
3.搜寻第一个或最后一个可能位置
ForwardIterator
lower_bound(ForwardIterator beg,ForwardIterator end,const T& value)
ForwardIterator
lower_bound(ForwardIterator beg,ForwardIterator end,const T& value,
BinaryPredicate op)
ForwardIterator
upper_bound(ForwardIterator beg,ForwardIterator end,const T& value)
ForwardIterator
upper_bound(ForwardIterator beg,ForwardIterator end,const T& value,
BinaryPredicate op)
1.lower_bound()返回第一个“大于等于value”的元素位置。
2.upper_bound()返回第一个“大于value”元素的位置
以下程序示范lower_bound()和upper_bound()的用法
1 #include "algostuff.hpp"
2 using namespace std;
3
4 int main()
5 {
6 list<int> coll;
7 INSERT_ELEMENTS(coll,1,9);
8 INSERT_ELEMENTS(coll,1,9);
9 coll.sort();
10 PRINT_ELEMENTS(coll);
11 list<int>::iterator pos1,pos2;
12 pos1=lower_bound(coll.begin(),coll.end(),5);
13 pos2=upper_bound(coll.begin(),coll.end(),5);
14 cout<<"5 could get position "
15 <<distance(coll.begin(),pos1)+1
16 <<" up to "
17 <<distance(coll.begin(),pos2)+1
18 <<" without breaking the sorting"<<endl;
19 coll.insert(lower_bound(coll.begin(),coll.end(),3),3);
20 coll.insert(upper_bound(coll.begin(),coll.end(),7),7);
21 PRINT_ELEMENTS(coll);
22 }
3.搜寻第一个和最后一个可能位置
pair<ForwardIterator,ForwardIterator>
equal_range(ForwardIterator beg,ForwardIterator end,const T& value)
pair<ForwardIterator,ForwardIterator>
equal_range(ForwardIterator beg,ForwardIterator end,const T& value,
BinaryPredicate op)
返回值与下式等效: make_pair(lower_bound(...),upper_bound(...))
以下程序展示equal_range()的用法
1 #include "algostuff.hpp"
2 using namespace std;
3
4 bool bothEvenOrOdd(int elem1,int elem2)
5 {
6 return elem1%2==elem2%2;
7 }
8
9 int main()
10 {
11 vector<int> coll1;
12 list<int> coll2;
13 INSERT_ELEMENTS(coll1,1,7);
14 INSERT_ELEMENTS(coll2,3,9);
15 PRINT_ELEMENTS(coll1,"coll1: ");
16 PRINT_ELEMENTS(coll2,"coll2: ");
17 if(equal(coll1.begin(),coll1.end(),coll2.begin()))
18 cout<<"coll1==coll2"<<endl;
19 else
20 cout<<"coll1!=coll2"<<endl;
21 if(equal(coll1.begin(),coll1.end(),coll2.begin(),bothEvenOrOdd))
22 cout<<"even and odd elements correspond"<<endl;
23 else
24 cout<<"even and odd elements do not correspond"<<endl;
25 }
合并元素(Merging)
1.两个已序集合的总和
OutputIterator
merge(InputIterator source1Beg,InputIterator source1End,
InputIterator source2Beg,InputIterator source2End,
OutputIterator destBeg)
OutputIterator
merge(InputIterator source1Beg,InputIterator source1End,
InputIterator source2Beg,InputIterator source2End,
OutputIterator destBeg,BinaryPredicate op)
1.两者都是将两个源区间的元素合并，使得“以destBeg起始的目标区间”内含两个源区间所有元素。
2.目标区间内的所有元素都将按顺序排序
下面这个例子展示merge()的用法
1 #include <iterator>
2 #include "algostuff.hpp"
3 using namespace std;
4
5 int main()
6 {
7 list<int> coll1;
8 set<int> coll2;
9 INSERT_ELEMENTS(coll1,1,6);
10 INSERT_ELEMENTS(coll2,3,8);
11 PRINT_ELEMENTS(coll1,"coll1: ");
12 PRINT_ELEMENTS(coll2,"coll2: ");
13 cout<<"merged: ";
14 merge(coll1.begin(),coll1.end(),coll2.begin(),coll2.end(),ostream_iterator<int>(cout," "));
15 cout<<endl;
16 }
2.两个已序集合的并集
OutputIterator
set_union(InputIterator source1Beg,InputIterator source1End,
InputIterator source2Beg,InputIterator source2End,
OutputIterator destBeg)
OutputIterator
set_union(InputIterator source1Beg,InputIterator source1End,
InputIterator source2Beg,InputIterator source2End,
OutputIterator destBeg,BinaryPredicate op)
与merge不一样的是，目标区间的元素要不来自第一源区间，要不就来自第二源区间，或是同时来自两个源区间。例如：
source1:1 2 2 4 6 7 7 9
source2:2 2 2 3 6 6 8 9
dest:1 2 2 2 3 4 6 6 7 7 8 9
3.两个已序集合的交集
OutputIterator
set_intersection(InputIterator source1Beg,InputIterator source1End,
InputIterator source2Beg,InputIterator source2End,
OutputIterator destBeg)
OutputIterator
set_intersection(InputIterator source1Beg,InputIterator source1End,
InputIterator source2Beg,InputIterator source2End,
OutputIterator destBeg,BinaryPredicate op)
4.两个已序集合的差集
OutputIterator
set_difference(InputIterator source1Beg,InputIterator source1End,
InputIterator source2Beg,InputIterator source2End,
OutputIterator destBeg)
OutputIterator
set_difference(InputIterator source1Beg,InputIterator source1End,
InputIterator source2Beg,InputIterator source2End,
OutputIterator destBeg,BinaryPredicate op)
目标区间的元素只存在于第一源区间，不存在与第二源区间。