STL算法(Algorithms):合并(Merge)

1、merge：将两个序列合并成一个新的序列，并对新的序列排序
原型：
template <class InputIterator1, class InputIterator2, class OutputIterator>
OutputIterator merge ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,OutputIterator result );
template <class InputIterator1, class InputIterator2,class OutputIterator, class Compare>
OutputIterator merge ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,OutputIterator result, Compare comp );
示例：

// mergealgorithmexample
#include < iostream >
#include < algorithm >
#include < vector >
using namespace std;

int main(){
int first[] = { 5 , 10 , 15 , 20 , 25 };
int second[] = { 50 , 40 , 30 , 20 , 10 };
vector < int > v( 10 );
vector < int > ::iteratorit;

sort(first,first + 5 );
sort(second,second + 5 );
merge(first,first + 5 ,second,second + 5 ,v.begin());

cout << " Theresultingvectorcontains: " ;
for (it = v.begin();it != v.end(); ++ it)
cout << " " << * it;

cout << endl;

return 0 ;
}

2、inplace_merge：将两个序列合并成一个新的序列,并对新的序列进行归并排序(这两个序列必须要进过排序)
原型：
template <class BidirectionalIterator>
void inplace_merge ( BidirectionalIterator first, BidirectionalIterator middle,
BidirectionalIterator last );

template <class BidirectionalIterator, class Compare>
void inplace_merge ( BidirectionalIterator first, BidirectionalIterator middle,
BidirectionalIterator last, Compare comp );
示例:

// inplace_mergeexample
#include < iostream >
#include < algorithm >
#include < vector >
using namespace std;

int main(){
int first[] = { 5 , 10 , 15 , 20 , 25 };
int second[] = { 50 , 40 , 30 , 20 , 10 };
vector < int > v( 10 );
vector < int > ::iteratorit;

sort(first,first + 5 );
sort(second,second + 5 );

copy(first,first + 5 ,v.begin());
copy(second,second + 5 ,v.begin() + 5 );

inplace_merge(v.begin(),v.begin() + 5 ,v.end());

cout << " Theresultingvectorcontains: " ;
for (it = v.begin();it != v.end(); ++ it)
cout << " " << * it;

cout << endl;

return 0 ;
}

3、includes：测试是一个序列是否在另一个序列中
原型：
template <class InputIterator1, class InputIterator2>
bool includes ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2 );
template <class InputIterator1, class InputIterator2, class Compare>
bool includes ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, Compare comp );
示例:

// includesalgorithmexample
#include < iostream >
#include < algorithm >
using namespace std;

bool myfunction( int i, int j){ return i < j;}

int main(){
int container[] = { 5 , 10 , 15 , 20 , 25 , 30 , 35 , 40 , 45 , 50 };
int continent[] = { 40 , 30 , 20 , 10 };

sort(container,container + 10 );
sort(continent,continent + 4 );

// usingdefaultcomparison:
if (includes(container,container + 10 ,continent,continent + 4 ))
cout << " containerincludescontinent! " << endl;

// usingmyfunctionascomp:
if (includes(container,container + 10 ,continent,continent + 4 ,myfunction))
cout << " containerincludescontinent! " << endl;

return 0 ;
}

4、set_union：和merge类似，不过新序列中没有重复的元素
原型：
template <class InputIterator1, class InputIterator2, class OutputIterator>
OutputIterator set_union ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,OutputIterator result );
template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
OutputIterator set_union ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,OutputIterator result, Compare comp );
示例：

// set_unionexample
#include < iostream >
#include < algorithm >
#include < vector >
using namespace std;

int main(){
int first[] = { 5 , 10 , 15 , 20 , 25 };
int second[] = { 50 , 40 , 30 , 20 , 10 };
vector < int > v( 10 ); // 0000000000
vector < int > ::iteratorit;

sort(first,first + 5 ); // 510152025
sort(second,second + 5 ); // 1020304050

it = set_union(first,first + 5 ,second,second + 5 ,v.begin());
// 51015202530405000

cout << " unionhas " << int (it - v.begin()) << " elements.\n " ;

return 0 ;
}

5、set_intersection：两个序列的交集
原型：
template <class InputIterator1, class InputIterator2, class OutputIterator>
OutputIterator set_intersection ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,OutputIterator result );
template <class InputIterator1, class InputIterator2,class OutputIterator, class Compare>
OutputIterator set_intersection ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,OutputIterator result, Compare comp );
示例：

// set_intersectionexample
#include < iostream >
#include < algorithm >
#include < vector >
using namespace std;

int main(){
int first[] = { 5 , 10 , 15 , 20 , 25 };
int second[] = { 50 , 40 , 30 , 20 , 10 };
vector < int > v( 10 ); // 0000000000
vector < int > ::iteratorit;

sort(first,first + 5 ); // 510152025
sort(second,second + 5 ); // 1020304050

it = set_intersection(first,first + 5 ,second,second + 5 ,v.begin());
// 102000000000

cout << " intersectionhas " << int (it - v.begin()) << " elements.\n " ;

return 0 ;
}

6、set_difference：序列(first1,last1)不在序列(first2,last2)中的元素
原型：
template <class InputIterator1, class InputIterator2, class OutputIterator>
OutputIterator set_intersection ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,outputIterator result );
template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
OutputIterator set_intersection ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,OutputIterator result, Compare comp );
示例：

// set_differenceexample
#include < iostream >
#include < algorithm >
#include < vector >
using namespace std;

int main(){
int first[] = { 5 , 10 , 15 , 20 , 25 };
int second[] = { 50 , 40 , 30 , 20 , 10 };
vector < int > v( 10 ); // 0000000000
vector < int > ::iteratorit;

sort(first,first + 5 ); // 510152025
sort(second,second + 5 ); // 1020304050

it = set_difference(first,first + 5 ,second,second + 5 ,v.begin());
// 515250000000

cout << " differencehas " << int (it - v.begin()) << " elements.\n " ;

return 0 ;
}

7、set_symmetric_difference：所有不在序列(first1,last1)和序列(first2,last2)中的元素
原型：
template <class InputIterator1, class InputIterator2, class OutputIterator>
OutputIterator set_symmetric_difference ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,OutputIterator result );
template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
OutputIterator set_symmetric_difference ( InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,OutputIterator result, Compare comp );
示例：

// set_symmetric_differenceexample
#include < iostream >
#include < algorithm >
#include < vector >
using namespace std;

int main(){
int first[] = { 5 , 10 , 15 , 20 , 25 };
int second[] = { 50 , 40 , 30 , 20 , 10 };
vector < int > v( 10 ); // 0000000000
vector < int > ::iteratorit;

sort(first,first + 5 ); // 510152025
sort(second,second + 5 ); // 1020304050

it = set_symmetric_difference(first,first + 5 ,second,second + 5 ,v.begin());
// 515253040500000

cout << " symmetricdifferencehas " << int (it - v.begin()) << " elements.\n " ;

return 0 ;
}