1920. Build Array from Permutation

class Solution {
    public int[] buildArray(int[] nums) {
        int CONST = 1001;

        for(int i = 0; i < nums.length; i++) {
            int a = nums[i];
            int b = nums[a]%CONST;
            nums[i] = a + b*CONST;
        }

        for(int i = 0; i < nums.length; i++) {
            nums[i] /= CONST;
        }

        return nums;

    }
}