20240513，常用算法（查找，排序，拷贝替换）

做着一些和考试无关的事情

常用查找算法——续

FIND_IF

find_if //按条件查找元素，返回迭代器POS / END()
find_if(beg,end,_Fred) _Fred函数或谓词（返回BOOL类型的仿函数）

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
//find_if  //按条件查找元素    find_if(beg,end,_Fred)_Fred函数或谓词（返回BOOL类型的仿函数）
class Greater {
public:
	bool operator()(int val) {
		return val>5;
	}
};
class Person {
public:
	Person(string n, int a) {
		this->_name = n;
		this->_age = a;
	}
	bool operator==(const Person& p) {
		if (this->_name == p._name && this->_age == p._age) {
			return true;
		}
		else {
			return false;
		}
	}
	string _name;
	int _age;
};
class Greater02 {
public:
	bool operator()(const Person &p) {
		return p._age==9;
	}
};
void test01() {
	vector<int>v;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
	}
	vector<int>::iterator it=find_if(v.begin(), v.end(), Greater());
	if (it == v.begin()) {
		cout << " no find" << endl;
	}
	else {
		cout << "find :  " <<*it<< endl;
	}
}
void test02() {
	vector<Person>p;
	Person p0("fsdef", 23);
	Person p1("复合工艺", 28);
	Person p2("粉色", 9);
	Person p3("得分·", 45);
	Person p4("啊上网服务", 53);
	p.push_back(p0);
	p.push_back(p1);
	p.push_back(p2);
	p.push_back(p3);
	p.push_back(p4);
	vector<Person>::iterator it = find_if(p.begin(), p.end(), Greater02());
	if (it == p.begin()) {
		cout << " no find" << endl;
	}
	else {
		cout << "find :  " << it->_name<<it->_age<< endl;
	}
}
int main() {
	test01();
	test02();
	return 0;
}

ADJACENT_FIND

adjacent_find //查找相邻重复元素
adjacent_find(begin,end)返回相邻元素的第一个的POS

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
//adjacent_find  //查找相邻重复元素   adjacent_find(begin,end)返回相邻元素的第一个的POS
class Person {
public:
	Person(string n, int a) {
		this->_name = n;
		this->_age = a;
	}
	bool operator==(const Person& p) {
		if (this->_name == p._name && this->_age == p._age) {
			return true;
		}
		else {
			return false;
		}
	}
	string _name;
	int _age;
};
void test01() {
	vector<int>v;
	v.push_back(0);
	v.push_back(1);
	v.push_back(0);
	v.push_back(3);
	v.push_back(3);
	vector<int>::iterator it = adjacent_find(v.begin(), v.end());
	if (it == v.begin()) {
		cout << " no find" << endl;
	}
	else {
		cout << "find :  " <<*it<< endl;
	}
}
void test02() {
	vector<Person>p;
	Person p1("复合工艺", 28);
	Person p2("粉色", 9);
	Person p3("得分·", 45);
	p.push_back(p2);
	p.push_back(p1);
	p.push_back(p2);
	p.push_back(p3);
	p.push_back(p3);
	vector<Person>::iterator it = adjacent_find(p.begin(), p.end());
	if (it == p.begin()) {
		cout << " no find" << endl;
	}
	else {
		cout << "find :  " << it->_name<<it->_age<< endl;
	}
}
int main() {
	test01();
	test02();
	return 0;
}

BINARY_SEARCH

binary_search //二分法查找
bool binary_search(beg,end,value) //无序序列中不可用

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
//binary_search  //二分法查找   bool binary_search(beg,end,value)//无序序列中不可用

void test01() {
	vector<int>v;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
	}
	if (binary_search(v.begin(),v.end(),7)) {
		cout << " no find" << endl;
	}
	else {
		cout << "find :  " << endl;
	}
}
void test02() {
	
}
int main() {
	test01();
	test02();
	return 0;
}

COUNT

count //统计元素个数 count(beg,end,value)

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
//count  //统计元素个数   count(beg,end,value)
class Person {
public:
	Person(string n, int a) {
		this->_name = n;
		this->_age = a;
	}
	bool operator==(const Person& p) {
		if (this->_name == p._name && this->_age == p._age) {
			return true;
		}
		else {
			return false;
		}
	}
	string _name;
	int _age;
};
void test01() {
	vector<int>v;
	v.push_back(0);
	v.push_back(0);
	v.push_back(0);
	v.push_back(3);
	v.push_back(3);
	int it=count(v.begin(), v.end(), 0);
	if (it==0) {
		cout << " no find" << endl;
	}
	else {
		cout << "find :  " <<it<<"   ge" << endl;
	}
}
void test02() {
	vector<Person>p;
	Person p1("复合工艺", 28);
	Person p2("粉色", 9);
	Person p3("得分·", 45);
	p.push_back(p2);
	p.push_back(p3);
	p.push_back(p2);
	p.push_back(p3);
	p.push_back(p3);
	int it = count(p.begin(), p.end(), p1);
	if (it == 0) {
		cout << " no find" << endl;
	}
	else {
		cout << "find :  " << it << "   ge" << endl;
	}
}
int main() {
	test01();
	test02();
	return 0;
}

COUNT_IF

count_if //按条件统计元素个数 count_if(beg,end,——Pred)

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
//count_if  //按条件统计元素个数    count_if(beg,end,_Pred)
class grater {
public:
	bool operator()(int val) {
		return val > 5;
	}
};

class Person {
public:
	Person(string n, int a) {
		this->_name = n;
		this->_age = a;
	}
	/*bool operator==(const Person& p) {
		if (this->_name == p._name && this->_age == p._age) {
			return true;
		}
		else {
			return false;
		}
	}*/
	string _name;
	int _age;
};
class grater02 {
public:
	bool operator()(const Person &p) {
		return p._age > 5;
	}
};
void test01() {
	vector<int>v;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
	}
	int it=count_if(v.begin(), v.end(), grater());
	if (it==0) {
		cout << " no find" << endl;
	}
	else {
		cout << "find :  " <<it<<"   ge" << endl;
	}
}
void test02() {
	vector<Person>p;
	Person p2("粉色", 4);
	Person p3("得分·", 45);
	p.push_back(p2);
	p.push_back(p3);
	p.push_back(p2);
	p.push_back(p3);
	p.push_back(p3);
	int it = count_if(p.begin(), p.end(), grater02());
	if (it == 0) {
		cout << " no find" << endl;
	}
	else {
		cout << "find :  " << it << "   ge" << endl;
	}
}
int main() {
	test01();
	test02();
	return 0;
}

常用排序算法

sort //对容器内元素进行排序
random_shuffle //洗牌，指定范围内顺序变随机
merge //容器元素合并，并存储道另一容器中
reverse //反转指定范围的元素

SORT

sort //对容器内元素进行排序 sort(beg,end,_Pred/谓词)

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
/*
sort  //对容器内元素进行排序
sort(beg,end,_Pred/谓词)
*/
class grater {
public:
	bool operator()(int v1,int v2) {
		return v1>v2;
	}
};

class Person {
public:
	Person(string n, int a) {
		this->_name = n;
		this->_age = a;
	}
	/*bool operator==(const Person& p) {
		if (this->_name == p._name && this->_age == p._age) {
			return true;
		}
		else {
			return false;
		}
	}*/
	string _name;
	int _age;
};
class grater02 {
public:
	bool operator()(const Person &p1,const Person &p2) {
		return p1._age > p2._age;
	}
};
void test01() {
	vector<int>v;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
	}
	for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
		cout << *it << " ";
	}
	cout << endl;
	sort(v.begin(), v.end(), grater());
	for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
		cout << *it << " ";
	}
	cout << endl;
	v.push_back(3);
	sort(v.begin(), v.end(), greater<int>());
	for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
		cout << *it << " ";
	}
	cout << endl;
}
void test02() {
	vector<Person>v;
	Person p0("fsdef", 23);
	Person p1("复合工艺", 28);
	Person p2("粉色", 9);
	Person p3("得分·", 45);
	Person p4("啊上务", 53);
	v.push_back(p0);
	v.push_back(p1);
	v.push_back(p2);
	v.push_back(p3);
	v.push_back(p4);
	for (vector<Person>::iterator it = v.begin(); it != v.end(); it++) {
		cout <<"name: " << it->_name << "\tage:" << it->_age << endl;
	}
	cout << endl;
	sort(v.begin(), v.end(), grater02());
	for (vector<Person>::iterator it = v.begin(); it != v.end(); it++) {
		cout << "name: " << it->_name << "\tage:" << it->_age << endl;
	}
	cout << endl;
}
int main() {
	test01();
	test02();
	return 0;
}

RANDOM_SHUFFLE

random_shuffle //洗牌，指定范围内顺序变随机
random_shuffle(beg,end)——加上随机数种子

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

class Person {
public:
	Person(string n, int a) {
		this->_name = n;
		this->_age = a;
	}
	string _name;
	int _age;
};
void test01() {
	srand((unsigned int)time(NULL));//加上随机数种子
	vector<int>v;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
	}
	for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
		cout << *it << " ";
	}
	cout << endl;
	random_shuffle(v.begin(), v.end());
	for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
		cout << *it << " ";
	}
	cout << endl;
	
}
void test02() {
	srand((unsigned int)time(NULL));//加上随机数种子
	vector<Person>v;
	Person p0("fsdef", 2);
	Person p1("复合工艺", 28);
	Person p2("粉色", 29);
	Person p3("得分·", 45);
	Person p4("啊上务", 53);
	v.push_back(p0);
	v.push_back(p1);
	v.push_back(p2);
	v.push_back(p3);
	v.push_back(p4);
	for (vector<Person>::iterator it = v.begin(); it != v.end(); it++) {
		cout <<"name: " << it->_name << "\tage:" << it->_age << endl;
	}
	cout << endl;
	random_shuffle(v.begin(), v.end());
	for (vector<Person>::iterator it = v.begin(); it != v.end(); it++) {
		cout << "name: " << it->_name << "\tage:" << it->_age << endl;
	}
	cout << endl;
}
int main() {
	test01();
	test02();
	return 0;
}

MERGE

merge //容器元素合并，并存储道另一容器中 PS：两个容器必须是有序的
merge(v1.beg ,v1.end ,v2.beg ,v2.end ,iterator dest） iterator dest目标容器开始迭代器
自定义类型失败

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

void test01() {
	vector<int>v;
	vector<int>v1;
	vector<int>vv;
	for (int i = 0; i < 4; i++) {
		v.push_back(i);
	}
	for (int i = 0; i < 6; i++) {
		v1.push_back(i+7);
	}
	vv.resize(v.size() + v1.size());  //先开辟空间
	merge(v.begin(), v.end(), v1.begin(), v1.end(), vv.begin());
	for (vector<int>::iterator it = vv.begin(); it != vv.end(); it++) {
		cout << *it << " ";
	}
	cout << endl;
}

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

REVERSE

reverse //反转指定范围的元素 reverse(beg,end)

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

class Person {
public:
	Person() {};
	Person(string n, int a) {
		this->_name = n;
		this->_age = a;
	}
	string _name;
	int _age;
};
void test01() {
	vector<int>v;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
	}
	for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
		cout << *it << " ";
	}
	cout << endl << "revers after：" << endl;
	reverse(v.begin(), v.end());
	for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
		cout << *it << " ";
	}
	cout << endl;
}
void test02() {
	vector<Person>v;
	Person p0("fsdef", 2);
	Person p1("复合工艺", 28);
	Person p2("粉色", 29);
	Person p3("得分·", 45);
	Person p4("啊上务", 53);
	v.push_back(p0);
	v.push_back(p1);
	v.push_back(p2);
	v.push_back(p3);
	v.push_back(p4);
	for (vector<Person>::iterator it = v.begin(); it != v.end(); it++) {
		cout << "name: " << it->_name << "\tage:" << it->_age << endl;
	}
	cout << endl << "revers after：" << endl;
	reverse(v.begin(), v.end());
	for (vector<Person>::iterator it = v.begin(); it != v.end(); it++) {
		cout << "name: " << it->_name << "\tage:" << it->_age << endl;
	}
}
int main() {
	test01();
	test02();
	return 0;
}

常用拷贝和替换算法

copy //容器内指定范围拷贝到另一容器中
replace //指定范围旧元素改为新元素
replace_if //指定范围旧元素替换为新元素
swap //互换两个容器元素

COPY

copy //容器内指定范围拷贝到另一容器中 copy(beg,end,iterator dest) ---iterator dest目标起始迭代器

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
/*
copy(beg,end,iterator dest)
*/
void myprint(int val) {
	cout << val << "  ";
}
void test01() {
	vector<int>v;
	vector<int>v2;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
	}
	v2.resize(v.size());//开辟空间
	copy(v.begin(), v.end(),v2.begin());
	for_each(v2.begin(), v2.end(), myprint);
	cout << endl;
}
void test02() {
	
}
int main() {
	test01();
	test02();
	return 0;
}

REPLACE

replace //指定范围旧元素改为新元素 replace(beg，end，old val，new val)

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
/*
replace(beg,end,old val,new val)
*/
class Person {
public:
	Person() {};
	Person(string n, int a) {
		this->_name = n;
		this->_age = a;
	}
	bool operator==(const Person &p) {
		if (this->_name == p._name && this->_age == p._age) {
			return true;
		}
		else {
			return false;
		}
	}
	string _name;
	int _age;
};
void myprint(int val) {
	cout << val << "  ";
}
void myprint02(Person p) {
	cout << "name: " << p._name << "\tage:" << p._age << endl;
}
void test01() {
	vector<int>v;
	for (int i = 0; i < 10; i++) {
		int t = i;
		if ((t % 2) == 0) {
			v.push_back(i);
		}
		else {
			v.push_back(0);
		}
	}
	for_each(v.begin(), v.end(), myprint);
	cout << endl;
	replace(v.begin(), v.end(),0,3000);
	for_each(v.begin(), v.end(), myprint);
	cout << endl;
}
void test02() {
	vector<Person>v;
	Person p2("粉色", 29);
	Person p3("得  分·", 45);
	v.push_back(p2);
	v.push_back(p2);
	v.push_back(p3);
	for_each(v.begin(), v.end(), myprint02);
	cout << endl;
	replace(v.begin(), v.end(), p2, p3);
	for_each(v.begin(), v.end(), myprint02);
	cout << endl;
}
int main() {
	test01();
	test02();
	return 0;
}

REPLACE_IF

replace_if //指定范围旧元素替换为新元素 replace_if(beg,end,_pred,new val)

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
/*
replace_if(beg,end,_pred,new val)
*/
class Person {
public:
	Person(string n, int a) {
		this->_name = n;
		this->_age = a;
	}
	bool operator==(const Person &p) {
		if (this->_name == p._name && this->_age == p._age) {
			return true;
		}
		else {
			return false;
		}
	}
	string _name;
	int _age;
};
void myprint(int val) {
	cout << val << "  ";
}
class greater5 {
public:
	bool operator()(int val) {
		return val > 5;
	}
};
class greater30 {
public:
	bool operator()(Person &p2) {
		return  p2._age<30;
	}
};
void myprint02(Person p) {
	cout << "name: " << p._name << "\tage:" << p._age << endl;
}
void test01() {
	vector<int>v;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
	}
	for_each(v.begin(), v.end(), myprint);
	cout << endl;
	replace_if(v.begin(), v.end(), greater5(), 3000);
	for_each(v.begin(), v.end(), myprint);
	cout << endl;
}
void test02() {
	vector<Person>v;
	Person p2("粉色", 29);
	Person p3("得  分·", 45);
	v.push_back(p2);
	v.push_back(p2);
	v.push_back(p3);
	for_each(v.begin(), v.end(), myprint02);
	cout << endl;
	replace_if(v.begin(), v.end(), greater30(), p3);
	for_each(v.begin(), v.end(), myprint02);
	cout << endl;
}
int main() {
	test01();
	test02();
	return 0;
}

SWAP

swap //互换两个容器元素 swap(container c1,container c2)

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
/*
replace_if(beg,end,_pred,new val)
*/
void myprint(int val) {
	cout << val << "  ";
}
void test01() {
	vector<int>v;
	vector<int>v1;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
		if(i<5){
			v1.push_back(0);
		}
	}
	cout << "swap before:" << endl;
	for_each(v.begin(), v.end(), myprint);
	cout << endl;
	for_each(v1.begin(), v1.end(), myprint);
	cout << endl;
	cout << "swap after:" << endl;
	swap(v, v1);
	for_each(v.begin(), v.end(), myprint);
	cout << endl;
	for_each(v1.begin(), v1.end(), myprint);
	cout << endl;
}
void test02() {
	
}
int main() {
	test01();
	test02();
	return 0;
}