C++进阶STL-常用集合算法

我就是我 2022-05-06 02:30 248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][2018101216241263]

--------------------

## 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 <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 < 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][20181012163146416]

--------------------

## 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 <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 < 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;
    }

结果：  
![在这里插入图片描述][20181012164329159]

[2018101216241263]: /images/20220506/9e1707658f9c4471bbc85ef9d70377af.png
[20181012163146416]: /images/20220506/7e4c12b6f3874ebba1be120fb7b53cea.png
[20181012164329159]: /images/20220506/aed19b283aa34125a78b6995ddfd25e0.png