1940번: 주몽

https://www.acmicpc.net/problem/1940

1940번: 주몽

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() 
{
	int N;  //재료의 개수
	int M;  //원하는 갑옷 고유번호
	vector<int> numbers; //재료들

	cin >> N >> M ;

	for (int i = 0; i < N; i++)
	{
		int num;
		cin >> num;
		numbers.push_back(num);
	}
	sort(numbers.begin(), numbers.end());
	numbers.push_back(0);

	int i = 0;
	int j = N-1;
	int count = 0;
 
	while (i<j)
	{
		int result = numbers[i] + numbers[j];

		if (result < M)
		{
			i++;
		}
		else if (result > M)
		{
			j--;
		}
		else
		{
			count++;
			i++;
			j--;
		}
	}
	cout << count << endl;

	return 0;
}