[BOJ] 18870. 좌표 압축

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

18870번: 좌표 압축

import java.io.*;
import java.util.Arrays;
import java.util.Comparator;
import java.util.StringTokenizer;

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());
        X[] x = new X[n];
        X[] ans = new X[n];

        StringTokenizer st = new StringTokenizer(br.readLine());
        for (int i = 0; i < n; ++i) {
            x[i] = new X(Integer.parseInt(st.nextToken()), i);
        }

        Arrays.sort(x, Comparator.comparingInt(o -> o.value));

        ans[0] = new X(0, x[0].index);
        for (int i = 1; i < n; ++i) {
            if (x[i].value == x[i - 1].value) {
                ans[i] = new X(ans[i - 1].value, x[i].index);
            } else {
                ans[i] = new X(ans[i - 1].value + 1, x[i].index);
            }
        }

        Arrays.sort(ans, Comparator.comparingInt(o -> o.index));

        StringBuilder builder = new StringBuilder();
        for(X x1: ans) {
            builder.append(x1.value).append(" ");
        }

        bw.write(builder.toString());

        bw.close();
        br.close();
    }

    public static class X {
        public int value;
        public int index;

        public X(int value, int index) {
            this.value = value;
            this.index = index;
        }
    }
}

• 정렬 문제
• 값과 인덱스를 쌍으로 정렬하면 풀리는 문제이다.