solution.java

import java.util.*;

class Solution {
    public int[] arrayRankTransform(int[] arr) {
        if (arr.length == 0) return new int[0];
        
        // Step 1: Create a sorted copy of the array
        int[] sortedArr = arr.clone();
        Arrays.sort(sortedArr);
        
        // Step 2: Create a map to store the rank of each element
        Map<Integer, Integer> rankMap = new HashMap<>();
        int rank = 1;
        
        // Step 3: Assign ranks to sorted elements
        for (int num : sortedArr) {
            if (!rankMap.containsKey(num)) {
                rankMap.put(num, rank++);
            }
        }
        
        // Step 4: Replace each element in the original array with its rank
        for (int i = 0; i < arr.length; i++) {
            arr[i] = rankMap.get(arr[i]);
        }
        
        return arr;
    }
}