includes,lower_bound,upper_bound,equal_range

C++ STL算法示例

最新推荐文章于 2023-03-16 09:25:14 发布

最新推荐文章于 2023-03-16 09:25:14 发布 · 71 阅读

本文介绍了C++标准模板库(STL)中的几个实用算法，包括includes、lower_bound、upper_bound及equal_range等函数的应用实例。通过具体代码展示了如何利用这些算法进行数据比较和查找。

直接代码如下：

//includes
#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
bool jiayibijiao(int a,int b){
	return a==b;
}
int main(){
	int a[]={1,2,3,4,5,6,7,8,9,10};
	int b[]={5,6,7,8,9};
	vector<int>v(a,a+10);//调用includes前要先排序
	vector<int>vv(b,b+5);
	sort(v.begin(),v.end());
	sort(vv.begin(),vv.end());
	if(includes(v.begin(),v.end(),vv.begin(),vv.end())){
		cout<<"v includes vv"<<endl;
	}else{
		cout<<"v not includes vv"<<endl;
	}

	sort(v.begin(),v.end());
	sort(vv.begin(),vv.end());
	if(includes(v.begin(),v.end(),vv.begin(),vv.end(),jiayibijiao)){
		cout<<"v includes vv+0"<<endl;
	}else{
		cout<<"v not includes vv+0"<<endl;
	}
	system("pause");
	return 0;
}

//lower_bound(),upper_bound()

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
bool nothing(int a,int b){
	return  a<b;
}
int main(){
	int a[]={1,3,4,5,5,5,6,7,8,9};
	vector<int>v(a,a+10);
	sort(v.begin(),v.end());//调用函数前要先排序
	vector<int>::iterator iter=lower_bound(v.begin(),v.end(),5);
	cout<<*iter<<endl;//指向第一个满足条件的元素
	iter=upper_bound(v.begin(),v.end(),5);
	cout<<*iter<<endl;//指向第一个不满足条件的元素
		
	vector<int>::iterator it=lower_bound(v.begin(),v.end(),5,nothing);
	cout<<"the first location:"<<distance(v.begin(),it)<<endl;
	it=upper_bound(v.begin(),v.end(),5,nothing);
	cout<<"the second location:"<<distance(v.begin(),it)<<endl;
	system("pause");
	return 0;
}

//equal_range
#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
int main(){
	int a[]={7,4,1,8,5,2,9,6,3,5,4,5,4,5,5};
	vector<int>v(a,a+15);
	sort(v.begin(),v.end());//先排序
	pair<vector<int>::iterator,vector<int>::iterator>fanwei;
	fanwei=equal_range(v.begin(),v.end(),5);//关联函数设置了这个成员函数，效果更佳
	cout<<"the first loaction:"<<distance(v.begin(),fanwei.first)<<endl;
	cout<<*(fanwei.first)<<endl;
	
	cout<<"the second location:"<<distance(v.begin(),fanwei.second)<<endl;
	cout<<*(fanwei.second)<<endl;
	system("pause");
	return 0;

}