C++ 알고리즘 체크리스트

#include <bits/stdc++.h>
using namespace std;

bool cmp(int a, int b) { //정렬
	//return a > b;
	if (a > b)
		return true;
	else
		return false;
}

void vectorPrac(){ //벡터
	vector<int> v;
	v.push_back(0);
	v.push_back(1);
	v.push_back(-1);

	sort(v.begin(), v.end(), cmp); //정렬 함수 사용자 정의

	for (int i = 0; i < v.size(); i++) {
		cout << v[i] << ' ';
	}
	cout << '\n';

	v.erase(v.begin() + 1); //특정 인덱스 원소 제거

	for (int i = 0; i < v.size(); i++) {
		cout << v[i] << ' ';
	}


	vector<string> strv;
	strv.push_back("abc\n");
	cout << strv[0];

	string a = "abcdef";
	string subs = a.substr(1, 3); //1번째부터 시작해서 길이 3만큼
	cout << subs << '\n';
}


void stackPrac(){ //스택
	stack<int> stk;
	stk.push(1);
	stk.pop();
	stk.push(5);
	stk.push(4);
	cout << "스택크기 = " << stk.size() << '\n';
	while(!stk.empty()){
		cout << stk.top() << ' ';
		stk.pop();
	}
	cout << '\n';
}

void queuePrac(){ //큐
	queue<int> q;
	q.push(1);
	q.push(2);
	cout << "큐 크기 = " << q.size() << '\n';
	while(!q.empty()){
		cout << q.front() << ' ';
		q.pop();
	}
	cout << '\n';
}

void mapPrac(){
	map<string, int> mp;
	mp.insert({"abc", 1});
	mp.insert({"def", 2});
	mp.insert({"abc", 3}); //이미 존재하는 key에 대해서 insert 하면 무시된다
	mp["abc"] = 3; //하지만 이렇게 수정하면 반영된다.
	for(auto itr = mp.begin() ; itr != mp.end() ; itr++){
		cout << itr->first << " " << itr->second << '\n';
		cout << itr->first << " " << mp[itr->first] << '\n';
	}
	cout << "맵 크기 = " << mp.size() << '\n';
	
}

void setPrac(){
	vector<int> v = {4,4,4,5,1,1,1,2,3};
	for(int i = 0 ; i < v.size() ; i++){
		cout << v[i] << ' ';
	}
	cout << '\n';
	
	set<int> st;
	for(int i = 0 ; i < v.size() ; i++){
		st.insert(v[i]);
	}
	for(auto itr = st.begin() ; itr != st.end() ; itr++){
		cout << *itr << ' ';
	}
	cout << '\n';
	
	set<int, greater<int> > bigSt;
	for(int i = 0 ; i < v.size() ; i++){
		bigSt.insert(v[i]);
	}
	for(auto itr = bigSt.begin() ; itr != bigSt.end() ; itr++){
		cout << *itr << ' ';
	}
	cout << '\n';
}
void priority_queuePrac(){
	priority_queue<int, vector<int>, less<int> > pq; //내림차순으로 나오는
	pq.push(9);
	pq.push(1);
	pq.push(4);
	pq.push(5);
	pq.push(2);
	while(!pq.empty()){
		cout << pq.top();
		pq.pop();
	}
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	vectorPrac();
	stackPrac();
	queuePrac();
	mapPrac();
	setPrac();
	priority_queuePrac();
	
}