20240514，算法（算数生成，集合）

还有一个大案例，那个就不急了，完结撒花，起码C++是打代码没什么大问题的完结，不像C，还要我返工/笑哭

常用算数生成算法

属于小算法，头文件**#include <numeric>**
accumulate //计算容器累计总和
fill //容器中添加元素

ACCUMULATE

accumulate //计算容器累计总和
accumulate(begin,end,val) /val==累加起始值

cpp 复制代码

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<numeric>
using namespace std;
/*
accumulate(begin,end,val)  //val==起始值
*/
void myprint(int val) {
	cout << val << "  ";
}
void test01() {
	vector<int>v;
	for (int i = 0; i <= 100; i++) {
		v.push_back(i);
	}
	int sum=accumulate(v.begin(), v.end(), 0);
	cout <<sum<< endl;
	sum = accumulate(v.begin(), v.end(), 1000);
	cout << sum << endl;

}
void test02() {
	
}
int main() {
	test01();
	test02();
	return 0;
}

FILL

fill //容器中添加元素 fill(begin,end,val)

cpp 复制代码

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<numeric>
using namespace std;
/*
fill(begin,end,val)  
*/
void myprint(int val) {
	cout << val << "  ";
}
void test01() {
	vector<int>v;
	v.resize(10);
	fill(v.begin(), v.end(), 1000);
	for_each(v.begin(), v.end(), myprint);
	cout << endl;
}
void test02() {
	
}
int main() {
	test01();
	test02();
	return 0;
}

常用集合算法

set_intersection //交集

set_union //并集

set_difference //差集
都必须是有序数列，返回迭代器

SET_INTERECTION

set_intersection //交集 set_intersection(beg1,end1,beg2,end2,iterator dest)返回迭代器

cpp 复制代码

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
//#include<numeric>
using namespace std;
/*
set_intersection(beg1,end1,beg2,end2,iterator dest)
*/
void myprint(int val) {
	cout << val << "  ";
}
void test01() {
	vector<int>v;
	vector<int>v1;
	vector<int>v2;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
		v1.push_back(i+5);
	}
	//v2.resize(v.size() < v1.size()?v.size():v1.size());//提前开辟
	v2.resize(min(v.size(), v1.size()));
	vector<int>::iterator iEnd = set_intersection(v.begin(), v.end(), v1.begin(), v1.end(), v2.begin());
	for_each(v2.begin(), v2.end(), myprint);
	cout << endl;
	for_each(v2.begin(), iEnd, myprint);//用返回的迭代器打印输出
}
void test02() {
	
}
int main() {
	test01();
	test02();
	return 0;
}

SET_UNION

set_union //并集 set_intersection(beg1,end1,beg2,end2,iterator dest)

cpp 复制代码

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;

void myprint(int val) {
	cout << val << "  ";
}
void test01() {
	vector<int>v;
	vector<int>v1;
	vector<int>v2;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
		v1.push_back(i+5);
	}
	v2.resize(v.size()+v1.size());
	vector<int>::iterator iEnd = set_union(v.begin(), v.end(), v1.begin(), v1.end(), v2.begin());
	for_each(v2.begin(), v2.end(), myprint);
	cout << endl;
	for_each(v2.begin(), iEnd, myprint);//用返回的迭代器打印输出
}
void test02() {
	
}
int main() {
	test01();
	test02();
	return 0;
}

SET_DIFFERENCE

set_difference //差集 set_difference (beg1,end1,beg2,end2,iterator dest)

cpp 复制代码

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;

void myprint(int val) {
	cout << val << "  ";
}
void test01() {
	vector<int>v;
	vector<int>v1;
	vector<int>v2;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
		v1.push_back(i+5);
	}
	v2.resize(v.size());
	vector<int>::iterator iEnd = set_difference(v.begin(), v.end(), v1.begin(), v1.end(), v2.begin());
	for_each(v2.begin(), v2.end(), myprint);
	cout << endl;
	for_each(v2.begin(), iEnd, myprint);//用返回的迭代器打印输出
	cout << endl;


	fill(v2.begin(), v2.end(), 0);
	for_each(v2.begin(), v2.end(), myprint);
	cout << endl;
	iEnd = set_difference(v1.begin(), v1.end(), v.begin(), v.end(), v2.begin());
	for_each(v2.begin(), iEnd, myprint);//用返回的迭代器打印输出
	cout << endl;
}
void test02() {
	
}
int main() {
	test01();
	test02();
	return 0;
}