STL_List简单使用

1简单应用 push_back

void test_list1()
{
	list<int> lt;
	lt.push_back(1);
	lt.push_back(2);
	lt.push_back(3);
	lt.push_back(4);
	list<int>::iterator it = lt.begin();
	while (it != lt.end())
	{
		cout << *it << ' ';
		++it;
	}
	cout << endl;
	for (auto e : lt)
	{
		cout << e << ' ';
	}
	cout << endl;

	it = lt.begin();
	//迭代器类型不支持
	//lt.erase(it + 3);
	string s("abnfajuefbnfnboqaefnqow");
	cout << s << endl;
	sort(s.begin(), s.end());
	cout << s << endl;
}

2push_back 与emplace的比较

struct A
{
public:
	A(int a1 = 1, int a2 = 1)
		:_a1(a1)
		,_a2(a2)
	{
		cout << "A(int a1 = 1, int a2 = 1)" << endl;
	}

	A(const A& aa)
		:_a1(aa._a1)
		,_a2(aa._a2)
	{
		cout << "A(const A& aa)" << endl;
	}

	int _a1;
	int _a2;
};

void test_list2()
{
	/*list<int> lt;
	lt.push_back(1);
	lt.emplace_back(2);
	lt.emplace_back(3);
	lt.emplace_back(4);
	for (auto e : lt)
	{
		cout << e << " ";
	}
	cout << endl;*/

	list<A> lt;
	A aa1(1, 1);
	lt.push_back(aa1);
	lt.push_back(A(2,2));
	//lt.push_back(3, 3);

	lt.emplace_back(aa1);
	lt.emplace_back(A(2,2));
	cout << endl;
	// 支持直接传构造A对象的参数emplace_back
	lt.emplace_back(3, 3);
}

insert与erase

void test_list3()
{
	list<int> lt;
	lt.push_back(1);
	lt.push_back(2);
	lt.push_back(3);
	lt.push_back(4);
	lt.push_back(5);
	lt.push_back(6);

	for (auto e : lt)
	{
		cout << e << " ";
	}
	cout << endl;

	auto it = lt.begin();
	int k = 3;
	while (k--)
	{
		++it;
	}

	lt.insert(it, 30);

	for (auto e : lt)
	{
		cout << e << " ";
	}
	cout << endl;

	int x = 0;
	cin >> x;
	it = find(lt.begin(), lt.end(), x);
	if (it != lt.end())
	{
		lt.erase(it);
	}

	for (auto e : lt)
	{
		cout << e << " ";
	}
	cout << endl;
}

sort merge

void test_list4()
{
	list<int> lt;
	lt.push_back(1);
	lt.push_back(20);
	lt.push_back(3);
	lt.push_back(5);
	lt.push_back(4);
	lt.push_back(5);
	lt.push_back(6);

	for (auto e : lt)
	{
		cout << e << " ";
	}
	cout << endl;

	// 升序
	// lt.sort();
	// 降序 - 仿函数
	// less<int> ls;
	// greater<int> gt;
	// lt.sort(gt);
	lt.sort(greater<int>());

	// lt.reverse();
	//reverse(lt.begin(), lt.end());

	for (auto e : lt)
	{
		cout << e << " ";
	}
	cout << endl;

	std::list<double> first, second;

	first.push_back(3.1);
	first.push_back(2.2);
	first.push_back(2.9);

	second.push_back(3.7);
	second.push_back(7.1);
	second.push_back(1.4);

	first.sort();
	second.sort();

	first.merge(second);
// (second is now empty)

}

uniqe去重

void test_list5()
{
	list<int> lt1, lt2;
	lt1.push_back(1);
	lt1.push_back(20);
	lt1.push_back(3);
	lt1.push_back(46);
	lt1.push_back(5);
	lt1.push_back(67);
	lt1.push_back(4);

	lt2.push_back(66);
	lt2.push_back(20);
	lt2.push_back(3);
	lt2.push_back(46);
	lt2.push_back(5);
	lt2.push_back(67);
	lt2.push_back(4);
	lt1.sort();
	lt2.sort();
	lt1.unique();
	lt2.unique();
	for (auto e : lt1)
	{
		cout << e << ' ';
	}
	cout << endl;
	for (auto e : lt2)
	{
		cout << e << ' ';
	}
	cout << endl;
}

vector与list效率对比

void test_op1()
{
	srand(time(NULL));
	const int N = 1000000;

	list<int> lt1;
	vector<int> v;

	for (int i = 0; i < N; ++i)
	{
		auto e = rand() ;
		lt1.push_back(e);
		v.push_back(e);
	}

	int begin1 = clock();
	// 排序
	sort(v.begin(), v.end());
	int end1 = clock();

	int begin2 = clock();
	lt1.sort();
	int end2 = clock();

	printf("vector sort:%d\n", end1 - begin1);
	printf("list sort:%d\n", end2 - begin2);
}
void test_op2()
{
	srand(time(NULL));
	const int N = 1000000;

	list<int> lt1;
	list<int> lt2;

	for (int i = 0; i < N; ++i)
	{
		auto e = rand() + i;
		lt1.push_back(e);
		lt2.push_back(e);
	}

	int begin1 = clock();
	// 拷贝vector
	vector<int> v(lt2.begin(), lt2.end());

	// 排序
	sort(v.begin(), v.end());

	// 拷贝回lt2
	lt2.assign(v.begin(), v.end());

	int end1 = clock();

	int begin2 = clock();
	lt1.sort();
	int end2 = clock();

	printf("list copy vector sort copy list sort:%d\n", end1 - begin1);
	printf("list sort:%d\n", end2 - begin2);
}

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