#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>

using namespace std;
/*
 vector：变长数组，倍增
 string：字符串 substr(), c_str()
 queue：push(), front(), pop()
 priority_queue：push(), front(), pop();
 stack：push(), pop()
 deque：双端队列
 set, map，multiset, multimap：基于红黑树，动态维护有序序列。
 unordered_multiset, unordered_multimap：基于哈希表
 bitset：压位。
 */
int main() {
    vector<int> a1(10);
    for(int n : a1) cout << n << " ";
    cout << endl;
    vector<int> a2(10, 3);
    for(int n: a2) printf("%d ", n);
    puts("");
    for(vector<int>::iterator i=a2.begin(); i!=a2.end(); i++) cout << *i << " ";
    puts("");
    cout << "a2.size() == " << a2.size() << endl;
    cout << "a2.empty() == " <<  a2.empty() << endl;
    a2.clear();
    puts("");
    pair<int, string> p;
    p.first = 1;
    p.second = "aaa";
    cout << p.first << endl;
    cout << p.second;
    p = make_pair(222,"222");
    p = {22,"xxx"};

    string str = "aaa";
    cout << str.size() << str.empty() << endl;
    str += "sss";
    string sub = str.substr(2,2); // 从第2个字母开始返回2个字符，超出则返回到最后一个字符
    cout << sub;
    puts("");

    queue<int> q;
    q.push(2);
    q.pop();
    q.size();
    cout << "empty? : " << q.empty() << endl;
    q.front();
    q.push(22);
    cout << "qback: " << q.back() << endl;
    cout << "qfront: " << q.front() << endl;

    priority_queue<int> heap;
    heap.push(2);
    heap.push(4);
    while(heap.size() > 0) cout << heap.top() << " ", heap.pop();
    puts("");
    priority_queue<int, vector<int>, greater<int>> heap2;
    heap2.push(2);
    heap2.push(4);
    while(heap2.size()>0) {
        cout << heap2.top() << " ";
        heap2.pop();
    }
    puts("");

    set<int> s;
    s.insert(1);
    s.insert(3);
    s.count(1);
    s.count(2);
    multiset<int> ms;
    ms.insert(1);ms.insert(1);
    cout << ms.count(1) << endl;
    ms.find(1);
    cout << *ms.lower_bound(2);// 大于x的最小数的迭代器
    ms.erase(2);

    map<int, int> m;
    m[2]=3;
}