蓝桥杯（3.7）

P1102 A-B 数对

import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int c = sc.nextInt();
		int[] res = new int[n+1];
		for(int i=1;i<=n;i++)
			res[i] = sc.nextInt();
		int sum = 0;
		for(int i=1;i<=n;i++) {
			for(int j=1;j<=n;j++) {
				if((res[i]-res[j]) == c) {
					sum++;
				}
			}
		}
		System.out.println(sum);
	}
}