LeetCode Practice (Day 19)

Achievements

About the problem

• Problem Number : 1389
• Problem Name : Create Target Array in the Given Order
• Problem difficulty : Easy 🟢
• Programming language used - Java

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

Approach Explanation

By utilizing an ArrayList to dynamically build the target array. For each element in the given nums array and its corresponding index in the index array, I used the ArrayList's add method to insert the value at the specified index. This way, I iterated through the arrays, progressively constructing the target array according to the given rules.

After completing the insertion process, I copied the elements from the ArrayList back to the original nums array. This final array represents the target array formed through the sequential insertions based on the specified indices. My approach aims for clarity and simplicity, leveraging the ArrayList's flexibility to efficiently handle insertions at specific positions and resulting in a concise solution to the problem.

If you have suggestions for improvement or would like to contribute to this solution, feel free to create a pull request. 🙌