1389. Create Target Array in the Given Order

Problem

Given two arrays of integers nums and index. Your task is to create target array under the following rules:

• Initially target array is empty.

• From left to right read nums[i] and index[i], insert at index index[i] the value nums[i] in target array.

• Repeat the previous step until there are no elements to read in nums and index.

Return the target array.

It is guaranteed that the insertion operations will be valid.

  Example 1:

Input: nums = [0,1,2,3,4], index = [0,1,2,2,1]
Output: [0,4,1,3,2]
Explanation:
nums       index     target
0            0        [0]
1            1        [0,1]
2            2        [0,1,2]
3            2        [0,1,3,2]
4            1        [0,4,1,3,2]

Example 2:

Input: nums = [1,2,3,4,0], index = [0,1,2,3,0]
Output: [0,1,2,3,4]
Explanation:
nums       index     target
1            0        [1]
2            1        [1,2]
3            2        [1,2,3]
4            3        [1,2,3,4]
0            0        [0,1,2,3,4]

Example 3:

Input: nums = [1], index = [0]
Output: [1]

  Constraints:

• 1 <= nums.length, index.length <= 100

• nums.length == index.length

• 0 <= nums[i] <= 100

• 0 <= index[i] <= i

Solution (Java)

class Solution {
    public int[] createTargetArray(int[] nums, int[] index) {
        List<Integer> list = new ArrayList<>();
        for (int i = 0; i < nums.length; i++) {
            list.add(index[i], nums[i]);
        }
        int[] target = new int[list.size()];
        for (int i = 0; i < target.length; i++) {
            target[i] = list.get(i);
        }
        return target;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).