C++进阶STL-常用集合算法-蒲公英云

C++进阶STL-常用集合算法

我就是我 2022-05-06 02:30 360阅读 0赞

交集

OutputIterator set_intersection (
InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,
OutputIterator result)
返回值是交集最后一个元素的下个元素的迭代器

例子：

#include "stdafx.h"
#include <iostream>
#include <algorithm>
#include <vector>
#include <time.h>
#include <numeric>
using namespace std;
void Print(int n)
{ 
    cout << " " << n;
}
int main()
{ 
    vector<int> v1;
    for (int i = 0; i < 10; i++)
    { 
        v1.push_back(i);
    }
    cout << "v1 : ";
    for_each(v1.begin(),v1.end(), Print); cout << endl;
    vector<int> v2;
    for (int i = 5; i < 20; i++)
    { 
        v2.push_back(i);
    }
    cout << "v2 : ";
    for_each(v2.begin(), v2.end(), Print); cout << endl;![在这里插入图片描述](https://img-blog.csdn.net/20181012162344674?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p6eWN6enlj/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70)
    vector<int> v3;
    v3.resize(min(v1.size(), v2.size()));
    vector<int>::iterator it=set_intersection(v1.begin(), v1.end(), v2.begin(), v2.end(), v3.begin());
    cout << "交集v3 : ";
    for_each(v3.begin(), it, Print); cout << endl;
    return 0;
}

结果：
在这里插入图片描述

并集

OutputIterator set_union (
InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,
OutputIterator result )
返回值：并集最后一个元素的下一个元素的迭代器

include “stdafx.h”
include
include
include
include
include
using namespace std;

void Print(int n)
{ 
    cout << " " << n;
}
int main()
{ 
    vector<int> v1;
    for (int i = 0; i < 7; i++)
    { 
        v1.push_back(i);
    }
    cout << "v1 : ";
    for_each(v1.begin(),v1.end(), Print); cout << endl;
    vector<int> v2;
    for (int i = 5; i < 10; i++)
    { 
        v2.push_back(i);
    }
    cout << "v2 : ";
    for_each(v2.begin(), v2.end(), Print); cout << endl;
    vector<int> v3;
    v3.resize(v1.size()+v2.size());
    vector<int>::iterator it=set_union(v1.begin(), v1.end(), v2.begin(), v2.end(), v3.begin());
    cout << "交集v3 : ";
    for_each(v3.begin(), it, Print); cout << endl;
    return 0;
}

结果：
在这里插入图片描述

差集：v1-(v1和v2的交集)

OutputIterator set_difference (
InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2,
OutputIterator result)
返回值：差集最后一个元素的下一个元素的迭代器

include “stdafx.h”
include
include
include
include
include
using namespace std;

void Print(int n)
{ 
    cout << " " << n;
}
int main()
{ 
    vector<int> v1;
    for (int i = 0; i < 7; i++)
    { 
        v1.push_back(i);
    }
    cout << "v1 : ";
    for_each(v1.begin(),v1.end(), Print); cout << endl;
    vector<int> v2;
    for (int i = 5; i < 10; i++)
    { 
        v2.push_back(i);
    }
    cout << "v2 : ";
    for_each(v2.begin(), v2.end(), Print); cout << endl;
    vector<int> v3;
    v3.resize(v1.size());
    vector<int>::iterator it= set_difference(v1.begin(), v1.end(), v2.begin(), v2.end(), v3.begin());
    cout << "差集 v3 : ";
    for_each(v3.begin(), it, Print); cout << endl;
    return 0;
}