常用STL

• • • vector
    • queue
    • map
    • bitset
    • pair

#include 
#include 

using namespace std;

int main(){
	vector whq = {1, 2, 3};
	cout << whq[1] << endl; // 2  支持随机访问
	whq.push_back(4);
	cout << whq.size() << endl; // 1 2 3 4 共4个
	whq.pop_back();
	cout << whq.size() << endl; // 1 2 3 共3个
	
	cout << whq.empty() << endl; //false-> 0
	whq.clear();
	cout << whq.empty() << endl << endl; // true->1
	
	// vector遍历
	whq = {1, 2, 3};
	for (int i = 0; i < whq.size(); i ++)
        cout << whq[i] << endl; // 1 2 3
    // 采用迭代器
    for (vector::iterator it = whq.begin(); it != whq.end(); it ++)
        cout << *it << endl; // 1 2 3
	
	cout << whq.front() << endl; // 1
	cout << whq.back() << endl; // 3
	

	
	return 0;
}

定义二维vector， 如n*m的vector。
vector> a(n, vector(m));

vector> st(n, vector(m));

#include 
#include  // 包括queue与priority_queue

using namespace std;

int main(){
	struct Rec{
		int a, b, c;
		bool operator> (const Rec& t) const {// 有sort则必须运算符重载，具体：小根堆重载>，大根堆重载＜
			return a > t.a;
		}
	};
	
	queue q;
	q.push(1);
	q.pop();
	cout << q.front() << endl; // 0
	cout << q.back() << endl; // 1
	cout << "   " << endl;
	
	
	priority_queue a; // 默认为大根堆 
	// 小根堆
	priority_queue, greater> b; 
	// 此处为结构体小根堆，需要手动重载>；若为大根堆则重载＜ 
	priority_queue, greater> d; 
	d.push({3, 2}); // 3 < 100
	d.push({100, 2});
	
	cout << d.top().a << endl; // 3 查看堆顶元素
	cout << d.top().b << endl; // 2
	cout << d.top().c << endl; // 0 未赋值则默认为0
	
	cout << d.empty() << endl; // false->0
	cout << d.size() << endl; // 2
	cout << "   " << endl;
	
	priority_queue> e;
	e.push({10, 2});
	e.push({3, 2});
	cout << e.top().first << endl; // 10
	
	return 0;
}

内部实现为红黑树

#include 
#include 

#include 
#include 

using namespace std;

int main(){
	bitset<1000> bb;
	bitset<1000> cc;
	bitset<1000> dd;
	bb[0] = 1;
	bb[2] = 1; // bb.set(2); reset则设为0
	cc[1] = 1;
	cout << (bb | cc).count() << endl; // 3 返回1的个数为3
	cout << bb[0] << " " << bb[1] << endl; // 1 0
	cout << bb.count() << endl; // 2
	cout << sizeof(bb) << endl; // 128
	
	return 0;
}

#include 

using namespace std;

int main(){
	pair a;
	a = {2018, "whq"};
	cout << a.first << " " << a.second << endl; // 2018 whq
	
	a = make_pair(1, "hello");
	cout << a.first << ' ' << a.second << endl; // 1 hello
	
	return 0;
}