BOJ13144 List of Unique Numbers

https://www.acmicpc.net/problem/13144

13144번: List of Unique Numbers

 

import java.util.*;
import java.io.*;
public class Main
{
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
        String[] input1 = br.readLine().split(" ");
        int[] arr = new int[n];
        for(int i=0; i<n;i++){
            arr[i] = Integer.parseInt(input1[i]);
        }
        
        
        int right=0;
        long count=0;
        HashSet<Integer> set = new HashSet();
        for(int left=0; left<n;left++){
            while(right<n && !set.contains(arr[right])){
                set.add(arr[right++]);
            }
            count+=(right-left);
            set.remove(arr[left]);
        }


        System.out.println(count);

        
	}
}