1345 - Jump Game IV.

Hard

Given an array of integers arr, you are initially positioned at the first index of the array.

In one step you can jump from index i to index:

• i + 1 where: i + 1 < arr.length.

• i - 1 where: i - 1 >= 0.

• j where: arr[i] == arr[j] and i != j.

Return the minimum number of steps to reach the last index of the array.

Notice that you can not jump outside of the array at any time.

Example 1:

Input: arr = 100,-23,-23,404,100,23,23,23,3,404

Output: 3

Explanation: You need three jumps from index 0 --> 4 --> 3 --> 9. Note that index 9 is the last index of the array.

Example 2:

Input: arr = 7

Output: 0

Explanation: Start index is the last index. You do not need to jump.

Example 3:

Input: arr = 7,6,9,6,9,6,9,7

Output: 1

Explanation: You can jump directly from index 0 to index 7 which is last index of the array.

Constraints:

• <code>1 <= arr.length <= 5 * 10⁴</code>

• <code>-10⁸<= arri<= 10⁸</code>