interviewstreet上的一个coding题

Problem Statement:

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Given N numbers , [N<=10^5] we need to count the total pairs of numbers that have a difference of K. [K>0 and K<1e9]

Input Format:
1st line contains N & K (integers).
2nd line contains N numbers of the set. All the N numbers are assured to be distinct.
Output Format:
One integer saying the no of pairs of numbers that have a diff K.

Sample Input #00:
5 2
1 5 3 4 2

Sample Output #00:
3

 

Sample Input #01:

10 1

363374326 364147530 61825163 1073065718 1281246024 1399469912 428047635 491595254 879792181 1069262793 

 

Sample Output #01:

0

 

Note: Java/C# code should be in a class named "Solution"

Read input from STDIN and write output to STDOUT. 

------------------------code-----------------------------------------

import java.util.HashMap;

import java.util.Map;

import java.util.Scanner;

public class Solution {

public static void main(String[] args) {

Scanner br=new Scanner(System.in);

int N = br.nextInt();

int K = br.nextInt();

int[] array = new int[N];

int count = 0;

Map map = new HashMap();

for (int i = 0 ; i < N ; i++  ){

array[i] = br.nextInt();

if(map.get(array[i])==null){

map.put(array[i],1);

}

else{

map.put(array[i],map.get(array[i])+1);

}

}

for(int i = 0 ; i < N ; i++  ){

if(map.get(array[i]+K)!=null){

count+=map.get(array[i]+K);

}

}

System.out.println(count);

}

}