백준 1822번 차집합

문제 링크입니다: https://www.acmicpc.net/problem/1822

STL set을 활용하기 좋은 문제입니다.

#include <iostream>

#include <set>

using namespace std;

 

set<int> s; //이진트리 역할

 

int main(void)

{

        ios_base::sync_with_stdio(0);

        cin.tie(0);

        int A, B;

        cin >> A >> B;

 

        for (int i = 0; i < A; i++)

        {

                 int num;

                 cin >> num;

 

                 s.insert(num);

        }

 

        for (int i = 0; i < B; i++)

        {

                 int num;

                 cin >> num;

 

                 auto it = s.find(num);

                 if (it == s.end())

                         continue;

                 else

                         s.erase(it);

        }

 

        cout << s.size() << "\n";

        for (auto num : s)

                 cout << num << " ";

        cout << "\n";

        return 0;

}

개발환경:Visual Studio 2017

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