BOJ18870 좌표압축

https://www.acmicpc.net/problem/18870

18870번: 좌표 압축

 

import java.io.*;
import java.util.*;
public class Main
{
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
		
		int n = Integer.parseInt(br.readLine());
		
		String[] input = br.readLine().split(" ");
		
		
		Set<Integer> hashset = new HashSet();
		HashMap<Integer,Integer> hashmap = new HashMap();
		
		
		for(String s: input){
		    hashset.add(Integer.valueOf(s));
		}
		Integer[] sortedInput= new Integer[hashset.size()];
		
		int index=0;
		for(Integer s: hashset){
		    sortedInput[index++] = s;
		}
		bw.write(hashset.toString());
		Arrays.sort(sortedInput);

		
		for(int i=0;i<sortedInput.length;i++){
		    hashmap.put(sortedInput[i],i);
		}
		
		for(int i=0; i<n-1;i++){
		    bw.write(hashmap.get(Integer.parseInt(input[i]))+" ");
		}
		bw.write(hashmap.get(Integer.parseInt(input[n-1]))+"");
		
		
		
		bw.flush();
	}
}

 

 

해시셋이 아닌 트리셋을 이용하면 정렬된 셋을 얻을 수 있다.

 

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

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[] inputs = br.readLine().split(" ");
        int[] xs = new int[N];
        Set<Integer> setX = new TreeSet<>();
        for (int i = 0; i < N; i++) {
            xs[i] = Integer.parseInt(inputs[i]);
            setX.add(xs[i]);
        }

        Map<Integer, Integer> sortedIndex = new HashMap<>();
        int idx = 0;
        for (int x : setX)
            sortedIndex.put(x, idx++);

        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        for (int i = 0; i < N; i++)
            bw.write(sortedIndex.get(xs[i]) + " ");
        bw.flush();
    }
}