STL常用算法
常用的遍历算法
for_each
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>void myPrint(int v)
{cout << v << " ";
}class MyPrint
{
public:void operator()(int v){cout << v << " ";}
};void test01()
{vector<int> v;for (int i = 0; i < 10; i++){v.push_back(i);}// 普通函数遍历for_each(v.begin(),v.end(),myPrint);cout << endl;// 函数对象遍历for_each(v.begin(), v.end(), MyPrint());cout << endl;
}
int main()
{test01();system("pause");return 0;
}transform
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>class Transform
{
public:int operator()(int v){return v + 100;}
};class Print
{
public:void operator()(int v){cout << v << " ";}};
void test01()
{vector<int> v;for (int i = 0; i < 10; i++){v.push_back(i);}vector<int> v2;//目标容器v2.resize(v.size());//提前开辟空间transform(v.begin(), v.end(), v2.begin(), Transform());for_each(v2.begin(), v2.end(), Print());cout << endl;
}
int main()
{test01();system("pause");return 0;
}常用的查找算法
对于自定义数据类型，一般需要重载==号 operator==
find
自定义数据类型
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
#include<string>// 内置数据类型
void test01()
{vector<int> v;for (int i = 0; i < 10; i++){v.push_back(i);}vector<int>::iterator pos = find(v.begin(), v.end(), 5);if (pos == v.end()){cout << "没有找到" << endl;}else{cout << "找到了" << *pos << endl;}
}class Person
{
public:bool operator==(Person p){if (this->name == p.name && this->age == p.age){return true;}return false;}Person(string name, int age){this->name = name;this->age = age;}string name;int age;
};// 自定义数据类型
void test02()
{vector<Person> v;v.push_back(Person("111",10));v.push_back(Person("222", 20));v.push_back(Person("333", 30));v.push_back(Person("444", 40));v.push_back(Person("555", 50));v.push_back(Person("666", 60));v.push_back(Person("777", 70));vector<Person>::iterator pos = find(v.begin(), v.end(), Person("222", 20));if (pos == v.end()){cout << "没有找到" << endl;}else{cout << "找到了" << endl<< "姓名：" << pos->name << " 年龄：" << pos->age << endl;}
}
int main()
{// test01();test02();system("pause");return 0;
}find_if
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
#include<string>class GreaterFive
{
public:bool operator()(int v){return v > 8;}
};
// 内置数据类型
void test01()
{vector<int> v;for (int i = 0; i < 10; i++){v.push_back(i);}vector<int>::iterator pos = find_if(v.begin(),v.end(), GreaterFive());if (pos == v.end()){cout << "没有找到" << endl;}else{cout << "找到了" << *pos << endl;}
}class Person
{
public:Person() {};bool operator()(Person p){return p.age > 50;}Person(string name, int age){this->name = name;this->age = age;}string name;int age;
};// 自定义数据类型
void test02()
{vector<Person> v;v.push_back(Person("111", 10));v.push_back(Person("222", 20));v.push_back(Person("333", 30));v.push_back(Person("444", 40));v.push_back(Person("555", 50));v.push_back(Person("666", 60));v.push_back(Person("777", 70));vector<Person>::iterator pos = find_if(v.begin(), v.end(), Person());if (pos == v.end()){cout << "没有找到" << endl;}else{cout << "找到了" << endl<< "姓名：" << pos->name << " 年龄：" << pos->age << endl;}
}
int main()
{// test01();test02();system("pause");return 0;
}adjacent_find
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
#include<string>void test01()
{vector<int> v;v.push_back(0);v.push_back(1);v.push_back(2);v.push_back(1);v.push_back(3);v.push_back(5);v.push_back(5);v.push_back(0);vector<int>::iterator pos = adjacent_find(v.begin(), v.end());if (pos == v.end()){cout << "没有找到" << endl;}else{cout << "找到了" << *pos << endl;}
}
int main()
{test01();system("pause");return 0;
}binary_search
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
#include<string>void test01()
{vector<int> v;for (int i = 0; i < 10; i++){v.push_back(i);}// 必须是有序的序列才能使用二分查找bool ret = binary_search(v.begin(), v.end(), 5);if (!ret){cout << "没有找到" << endl;}else{cout << "找到了" <<endl;}
}
int main()
{test01();system("pause");return 0;
}count
第三个参数中放的是统计的元素，自定义数据类型，元素内要放operator==
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
#include<string>// 内置数据类型
void test01()
{vector<int> v;for (int i = 0; i < 10; i++){v.push_back(i);}v.push_back(5);v.push_back(5);v.push_back(5);int ret = count(v.begin(), v.end(), 5);cout << ret << endl;
}class Person
{
public:bool operator==(Person p){return this->age == p.age;}//bool operator==(Person p)//{// if (this->name == p.name && this->age == p.age)// {// return true;// }// return false;//}Person(string name, int age){this->name = name;this->age = age;}string name;int age;
};// 自定义数据类型
void test02()
{vector<Person> v;v.push_back(Person("111", 10));v.push_back(Person("222", 40));v.push_back(Person("333", 30));v.push_back(Person("444", 40));v.push_back(Person("555", 40));v.push_back(Person("666", 40));v.push_back(Person("777", 70));int ret = count(v.begin(), v.end(), Person("888",40));cout << ret << endl;}
int main()
{// test01();test02();system("pause");return 0;
}count_if
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
#include<string>class Greater5
{
public:bool operator()(int v){return v > 5;}
};
// 内置数据类型
void test01()
{vector<int> v;for (int i = 0; i < 15; i++){v.push_back(i);}v.push_back(5);v.push_back(5);v.push_back(5);cout << count_if(v.begin(), v.end(), Greater5()) << endl;
}class Person
{
public:Person() {};bool operator()(Person p){return p.age > 10;}bool operator==(Person p){return this->age == p.age;}//bool operator==(Person p)//{// if (this->name == p.name && this->age == p.age)// {// return true;// }// return false;//}Person(string name, int age){this->name = name;this->age = age;}string name;int age;
};// 自定义数据类型
void test02()
{vector<Person> v;v.push_back(Person("111", 10));v.push_back(Person("222", 40));v.push_back(Person("333", 30));v.push_back(Person("444", 40));v.push_back(Person("555", 40));v.push_back(Person("666", 40));v.push_back(Person("777", 70));int ret = count_if(v.begin(), v.end(), Person());cout << ret << endl;}
int main()
{// test01();test02();system("pause");return 0;
}常用排序算法
sort
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
#include<functional>void print(int v)
{cout << v << " ";
}
void test01()
{vector<int> v;for (int i = 0; i < 15; i++){v.push_back(i);}v.push_back(5);v.push_back(5);v.push_back(5);// 默认从大到小sort(v.begin(), v.end());for_each(v.begin(), v.end(), print);cout << endl;sort(v.begin(), v.end(),greater<int>());for_each(v.begin(), v.end(), print);cout << endl;
}
int main()
{test01();system("pause");return 0;
}random_shuffle
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
#include<functional>void print(int v)
{cout << v << " ";
}
void test01()
{vector<int> v;for (int i = 0; i < 15; i++){v.push_back(i);}random_shuffle(v.begin(),v.end());for_each(v.begin(), v.end(), print);cout << endl;
}
int main()
{srand((unsigned int)time(NULL));test01();system("pause");return 0;
}merge
自定义数据类型还没高明白
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
#include<string>void print(int v)
{cout << v << " ";
}
// 内置数据类型
void test01()
{vector<int> v;vector<int> v2;for (int i = 0; i < 10; i++){v.push_back(i);v2.push_back(i + 2);}vector<int> vTarget;vTarget.resize(v.size() + v2.size());// 合并后仍然是有序的merge(v.begin(), v.end(), v2.begin(), v2.end(), vTarget.begin());for_each(vTarget.begin(),vTarget.end(), print);cout << endl;
}class Person
{
public:Person() {};bool operator<(const Person& p)const{return false;}bool operator==(Person p){if (this->name == p.name && this->age == p.age){return true;}return false;}Person(string name, int age){this->name = name;this->age = age;}string name;int age;
};//class Compare
//{
//public:
// bool operator()(Person p1, Person p2)
// {
// return p1.age > p2.age;
// }
//};
//void print2(Person p)
//{
// cout << "姓名:\t" << p.name << "\t"
// << "年龄:" << p.age << endl;
//}自定义数据类型
//void test02()
//{
// vector<Person> v;
// v.push_back(Person("111", 20));
// v.push_back(Person("222", 20));
// v.push_back(Person("333", 30));
// v.push_back(Person("444", 40));
// v.push_back(Person("555", 50));
// v.push_back(Person("666", 60));
// v.push_back(Person("777", 70));
// vector<Person> v2;
// v2.push_back(Person("888", 30));
// v2.push_back(Person("101", 40));
// v2.push_back(Person("999", 90));
//
// vector<Person> vTarget;
// vTarget.resize(v.size()+v2.size());
//
// merge(v.begin(), v.end(), v2.begin(), v2.end(), vTarget.begin(), Person());
//
// for_each(vTarget.begin(), vTarget.end(), print2);
// cout << endl;
//}
int main()
{test01();//test02();system("pause");return 0;
}reverse
常用的拷贝和替换算法
copy
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
void print(int v)
{cout << v << " ";
}
void test01()
{vector<int> v;for (int i = 0; i < 10; i++){v.push_back(i);}for_each(v.begin(), v.end(), print);cout << endl;vector<int> v2;v2.resize(v.size());copy(v.begin(),v.end(),v2.begin());for_each(v2.begin(), v2.end(), print);cout << endl;
}
int main()
{test01();system("pause");return 0;
}replace
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>class Print
{
public:void operator()(int v){cout << v << " ";}
};
void test01()
{vector<int> v;v.push_back(10);v.push_back(20);v.push_back(30);v.push_back(20);v.push_back(20);v.push_back(60);v.push_back(80);cout << "替换前" << endl;for_each(v.begin(),v.end(), Print());cout << endl;replace(v.begin(),v.end(),20,22);for_each(v.begin(), v.end(), Print());cout << endl;}
int main()
{test01();system("pause");return 0;
}replace_if
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>class Print
{
public:void operator()(int v){cout << v << " ";}
};class greater30
{
public:bool operator()(int v){return v >= 30;}
};
void test01()
{vector<int> v;v.push_back(10);v.push_back(20);v.push_back(30);v.push_back(20);v.push_back(20);v.push_back(60);v.push_back(80);cout << "替换前" << endl;for_each(v.begin(), v.end(), Print());cout << endl;cout << "替换后" << endl;replace_if(v.begin(), v.end(), greater30(), 11);for_each(v.begin(), v.end(), Print());cout << endl;}
int main()
{test01();system("pause");return 0;
}swap
两个容器必须同一种类型
大小可以不一样
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>class Print
{
public:void operator()(int v){cout << v << " ";}
};void test01()
{vector<int> v;v.push_back(10);v.push_back(20);v.push_back(30);v.push_back(20);v.push_back(20);v.push_back(60);v.push_back(80);vector<int> v2;v2.push_back(111);cout << "替换前" << endl;for_each(v.begin(), v.end(), Print());cout << endl;for_each(v2.begin(), v2.end(), Print());cout << endl;cout << "替换后" << endl;swap(v, v2);for_each(v.begin(), v.end(), Print());cout << endl;for_each(v2.begin(), v2.end(), Print());cout << endl;}
int main()
{test01();system("pause");return 0;
}常用算数生成算法
numeric 英文 数字的
accumulate
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<numeric>
#include<string>void test01()
{vector<int> v;for (int i = 0; i < 10; i++){v.push_back(i);}cout << accumulate(v.begin(), v.end(), 0) << endl;}
int main()
{test01();system("pause");return 0;
}对于自定义数据类型的应用
https://www.jb51.net/article/242034.htm
fill
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>class Print
{
public:void operator()(int v){cout << v << " ";}
};void test01()
{vector<int> v;v.resize(10);for_each(v.begin(), v.end(), Print());cout << endl;fill(v.begin(), v.end(), 100);for_each(v.begin(), v.end(), Print());cout << endl;
}
int main()
{test01();system("pause");return 0;
}常用的集合算法
set_intersection
返回交集的最后一个元素的下一个位置（我的是正确的，图片里是错误的）
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>class Print
{
public:void operator()(int v){cout << v << " ";}
};void test01()
{vector<int> v;vector<int> v2;for (int i = 0; i < 10; i++){v.push_back(i);v2.push_back(i + 5);}vector<int> v3;v3.resize(min(v.size(), v2.size()));vector<int>::iterator pos = set_intersection(v.begin(),v.end(),v2.begin(),v2.end(), v3.begin());// pos 指向最后一个元素的下一个位置cout << *pos << endl;for_each(v3.begin(), pos, Print());cout << endl;
}
int main()
{test01();system("pause");return 0;
}ste_union
返回交集的最后一个元素的下一个位置（我的是正确的，图片里是错误的）
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>class Print
{
public:void operator()(int v){cout << v << " ";}
};void test01()
{vector<int> v;vector<int> v2;for (int i = 0; i < 10; i++){v.push_back(i);v2.push_back(i + 5);}vector<int> v3;v3.resize(v.size()+v2.size());vector<int>::iterator pos = set_union(v.begin(), v.end(), v2.begin(), v2.end(), v3.begin());// pos 指向最后一个元素的下一个位置cout << *pos << endl;for_each(v3.begin(), pos, Print());cout << endl;
}
int main()
{test01();system("pause");return 0;
}set_difference
求谁的差集把谁的迭代器放前面
返回差集的最后一个元素的下一个位置（我的是正确的，图片里是错误的）
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>class Print
{
public:void operator()(int v){cout << v << " ";}
};void test01()
{vector<int> v;vector<int> v2;for (int i = 0; i < 10; i++){v.push_back(i);v2.push_back(i + 5);}vector<int> v3;v3.resize(max(v.size(),v2.size()));vector<int>::iterator pos = set_difference(v.begin(), v.end(), v2.begin(), v2.end(), v3.begin());// pos 指向最后一个元素的下一个位置// cout << *pos << endl;cout << "v的差集为：" << endl;for_each(v3.begin(), pos, Print());cout << endl;vector<int>::iterator pos2 = set_difference(v2.begin(), v2.end(), v.begin(), v.end(), v3.begin());cout << "v2的差集为：" << endl;for_each(v3.begin(), pos2, Print());cout << endl;}int main()
{test01();system("pause");return 0;
}
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