簡介

set_union
set_intersection
set_difference

set_union取并集

構(gòu)造一個(gè)有序序列惧磺，包含兩個(gè)有序序列的并集颖对。

        // TEMPLATE FUNCTION set_union
template<class _InIt1,
    class _InIt2,
    class _OutIt> inline
    _OutIt set_union(_InIt1 _First1, _InIt1 _Last1,
        _InIt2 _First2, _InIt2 _Last2, _OutIt _Dest)
    {   // OR sets [_First1, _Last1) and [_First2, _Last2), using operator<
    return (_STD set_union(_First1, _Last1, _First2, _Last2, _Dest,
        less<>()));
    }

 #if _ITERATOR_DEBUG_ARRAY_OVERLOADS
template<class _InIt1,
    class _InIt2,
    class _OutTy,
    size_t _OutSize> inline
    _OutTy *set_union(_InIt1 _First1, _InIt1 _Last1,
        _InIt2 _First2, _InIt2 _Last2, _OutTy (&_Dest)[_OutSize])
    {   // OR sets [_First1, _Last1) and [_First2, _Last2), array dest
    return (_STD set_union(_First1, _Last1, _First2, _Last2, _Dest,
        less<>()));
    }
 #endif /* _ITERATOR_DEBUG_ARRAY_OVERLOADS */

set_intersection

構(gòu)造一個(gè)有序序列，包含兩個(gè)有序序列的交集磨隘。

        // TEMPLATE FUNCTION set_intersection
template<class _InIt1,
    class _InIt2,
    class _OutIt> inline
    _OutIt set_intersection(_InIt1 _First1, _InIt1 _Last1,
        _InIt2 _First2, _InIt2 _Last2, _OutIt _Dest)
    {   // AND sets [_First1, _Last1) and [_First2, _Last2), using operator<
    return (_STD set_intersection(_First1, _Last1, _First2, _Last2, _Dest,
        less<>()));
    }

 #if _ITERATOR_DEBUG_ARRAY_OVERLOADS
template<class _InIt1,
    class _InIt2,
    class _OutTy,
    size_t _OutSize> inline
    _OutTy *set_intersection(_InIt1 _First1, _InIt1 _Last1,
        _InIt2 _First2, _InIt2 _Last2, _OutTy (&_Dest)[_OutSize])
    {   // AND sets [_First1, _Last1) and [_First2, _Last2), array dest
    return (_STD set_intersection(_First1, _Last1, _First2, _Last2, _Dest,
        less<>()));
    }
 #endif /* _ITERATOR_DEBUG_ARRAY_OVERLOADS */

set_difference

構(gòu)造一個(gè)有序序列训堆，該序列保留第一個(gè)有序序列中存在而第二個(gè)有序序列中不存在的元素。

        // TEMPLATE FUNCTION set_difference
template<class _InIt1,
    class _InIt2,
    class _OutIt> inline
    _OutIt set_difference(_InIt1 _First1, _InIt1 _Last1,
        _InIt2 _First2, _InIt2 _Last2,
        _OutIt _Dest)
    {   // take set [_First2, _Last2) from [_First1, _Last1), using operator<
    return (_STD set_difference(_First1, _Last1, _First2, _Last2, _Dest,
        less<>()));
    }

 #if _ITERATOR_DEBUG_ARRAY_OVERLOADS
template<class _InIt1,
    class _InIt2,
    class _OutTy,
    size_t _OutSize> inline
    _OutTy *set_difference(_InIt1 _First1, _InIt1 _Last1,
        _InIt2 _First2, _InIt2 _Last2,
        _OutTy (&_Dest)[_OutSize])
    {   // take set [_First2, _Last2) from [_First1, _Last1), array dest
    return (_STD set_difference(_First1, _Last1, _First2, _Last2, _Dest,
        less<>()));
    }
 #endif /* _ITERATOR_DEBUG_ARRAY_OVERLOADS */

注意

• 集合必須有序
• 目的集合的大小要提前分配
• 自定義類型需要重載<操作符

示例

#include "stdafx.h"
#include "stdafx.h"
#include "iostream"
#include "string"
#include "algorithm"
#include "vector"
#include "list"
#include <functional>
#include<numeric>
using namespace std;
class Student {
private:
    int number;
    string name;
public:
    Student() {
        this->number = 0;
        this->name = "";
    }
    Student(int number, string name) {
        cout << "構(gòu)造 " << number << " " << name.c_str() << endl;
        this->number = number;
        this->name = name;
    }
    Student(const Student & stu) {
        //cout << "copy構(gòu)造" <<stu.getNumber()<<" "<<stu.getName().c_str()<< endl;
        this->number = stu.getNumber();
        this->name = stu.getName();
    }
    ~Student() {
        //cout<<"析構(gòu) " << this->number << " " << this->name.c_str() << endl;
    }

    Student& operator=(const Student& stu) {
        this->number = stu.getNumber();
        this->name = stu.getName();
        return *this;
    }

    void print()const {
        cout << "print 》》 " << this->number << " " << this->name.c_str() << endl;
    }

    int getNumber() const {
        return this->number;
    }
    string getName()const {
        return this->name;
    }

    // 小于運(yùn)算符用于集合運(yùn)算  
    bool operator<(const Student &stu) const
    {
        return this->getNumber() < stu.getNumber();
    }
};

void printStuV(vector<Student> v) {
    cout << "開始遍歷vector<Student>============" << endl;
    for (vector<Student>::iterator it = v.begin(); it != v.end(); it++) {
        it->print();
    }
    cout << "結(jié)束遍歷vector<Student>============" << endl;
}
void printNum(vector<int>v) {
    cout << "開始遍歷vector<int>============" << endl;
    for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
        cout << *it << " ";
    }
    cout << endl;
    cout << "結(jié)束遍歷vector<int>============" << endl;
}

struct ReplaceFunc
{
    bool operator()(const Student & stu1) const {
        cout << "ReplaceFunc》》" << endl;
        return stu1.getNumber() >3;
    }
};

int main()
{
    //accumulate示例允扇，需要include<numeric>
    vector<int> vNum;
    vNum.push_back(1);
    vNum.push_back(2);
    vNum.push_back(3);
    vector<int> vNum2;
    vNum2.push_back(2);
    vNum2.push_back(3);
    vNum2.push_back(5);
    vector<int> vNum3;
    vNum3.resize(10);
    //取并集
    set_union(vNum.begin(),vNum.end(),vNum2.begin(),vNum2.end(),vNum3.begin());
    printNum(vNum3);
    fill(vNum3.begin(), vNum3.end(), 0);
    //交集
    set_intersection(vNum.begin(), vNum.end(), vNum2.begin(), vNum2.end(), vNum3.begin());
    printNum(vNum3);
    fill(vNum3.begin(), vNum3.end(), 0);
    //差集
    set_difference(vNum.begin(), vNum.end(), vNum2.begin(), vNum2.end(), vNum3.begin());
        printNum(vNum3);
    fill(vNum3.begin(), vNum3.end(), 0);


    cout << endl;
    //將輸入值賦給標(biāo)志范圍內(nèi)的所有元素读处。
    vector<Student> vStu;
    vector<Student> vStu2;
    vector<Student> vStu3;
    vStu3.resize(10);
    vStu.push_back(Student(1, "one"));
    vStu.push_back(Student(2, "two"));
    vStu.push_back(Student(3, "three"));
    vStu2.push_back(Student(3, "three_2"));
    vStu2.push_back(Student(4, "four"));
    //需要重載<操作符
    set_union(vStu.begin(), vStu.end(), vStu2.begin(), vStu2.end(), vStu3.begin());
    printStuV(vStu3);
}

結(jié)果：

jihe.png