[BOJ] 3273번 : 두 수의 합

코드

import java.lang.*;
import java.util.*;
import java.io.*;

public class Main {
	
	static int n, x;
	static int[] numbers;
	static int result = 0;
	
	public static void main(String[] args) {
		input();
		func();
		System.out.println(result);
	}
	
	static void input() {
		Scanner sc = new Scanner(System.in);
		
		n = sc.nextInt();
		numbers = new int[n];
		
		for (int i = 0; i < n; ++i) {
			numbers[i] = sc.nextInt();
		}
		
		x = sc.nextInt();
		
		sc.close();
	}
	
	static void func() {
		Arrays.sort(numbers);
		
		int left = 0;
		int right = n - 1;
		
		while (left < right) {
			int sum = numbers[left] + numbers[right];
			
			if (sum < x) {
				++left;
			} else {
				if (sum == x) {
					++result;
					++left;
				}
				
				--right;
			}
		}
	}
}