STL常用排序算法介绍

merge()

以下是排序和通用算法：提供元素排序策略

merge: 合并两个有序序列，存放到另一个序列。

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>

using namespace std;

void printV(vector<int> &v)
{
	for (vector<int>::iterator it = v.begin(); it != v.end(); ++it) {
		cout << *it << ' ';
	}
	cout << endl;
}

void play_merge()
{
	vector<int> v1;
	v1.push_back(1);
	v1.push_back(3);
	v1.push_back(5);

	vector<int> v2;
	v2.push_back(2);
	v2.push_back(4);
	v2.push_back(6);

	vector<int> v3;
	v3.resize(v1.size() + v2.size());
	merge(v1.begin(), v1.end(), v2.begin(), v2.end(), v3.begin());
	printV(v3);
	// 1 2 3 4 5 6
}

int main()
{
	play_merge();

	return 0;
}

sort()

sort: 以默认升序的方式重新排列指定范围内的元素。若要改排序规则，可以输入比较函数。

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <string>

using namespace std;

class Student
{
public:
	Student(string name, int id) : name(name), id(id) {}
	friend bool CompareStudent(Student &s1, Student &s2);

	string name;
	int id;
};

bool CompareStudent(Student &s1, Student &s2)
{
	return s1.id < s2.id;
}

void play_sort()
{
	Student s1("lucifer", 1);
	Student s2("zhang", 2);
	Student s3("yao", 3);
	Student s4("qi", 4);
	vector<Student> v;
	v.push_back(s4);
	v.push_back(s2);
	v.push_back(s1);
	v.push_back(s3);

	for (vector<Student>::iterator it = v.begin(); it != v.end(); ++it) {
		cout << "name: " << it->name << " id: " << it->id << endl;
	}
	/*
	name: qi id: 4
	name: zhang id: 2
	name: lucifer id: 1
	name: yao id: 3
	*/

	sort(v.begin(), v.end(), CompareStudent);

	for (vector<Student>::iterator it = v.begin(); it != v.end(); ++it) {
		cout << "name: " << it->name << " id: " << it->id << endl;
	}
	/*
	name: lucifer id: 1
	name: zhang id: 2
	name: yao id: 3
	name: qi id: 4
	*/
}

int main()
{
	play_sort();

	return 0;
}

random_shuffle()

random_shuffle: 对指定范围内的元素随机调整次序。

srand(time(0)); //设置随机种子

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <string>
#include <ctime>

using namespace std;

void printIntVector(vector<int> &v)
{
	for (vector<int>::iterator it = v.begin(); it != v.end(); ++it) {
		cout << *it << ' ';
	}
	cout << endl;
}

void play_random_shuffle()
{
	vector<int> v;
	v.push_back(1);
	v.push_back(3);
	v.push_back(5);
	v.push_back(7);
	v.push_back(9);

	printIntVector(v);
	// 1 3 5 7 9

	srand(time(0));
	random_shuffle(v.begin(), v.end());

	printIntVector(v);
	// 1 5 9 3 7
}

int main()
{
	play_random_shuffle();

	return 0;
}

reverse()

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <string>

using namespace std;

void printIntVector(vector<int> &v)
{
	for (vector<int>::iterator it = v.begin(); it != v.end(); ++it) {
		cout << *it << ' ';
	}
	cout << endl;
}

void play_reverse()
{
	vector<int> v;
	v.push_back(1);
	v.push_back(3);
	v.push_back(5);
	v.push_back(7);
	v.push_back(9);

	printIntVector(v);
	// 1 3 5 7 9

	reverse(v.begin(), v.end());

	printIntVector(v);
	// 9 7 5 3 1
}

int main()
{
	play_reverse();

	return 0;
}

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