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:
<li><code>i + 1</code> where: <code>i + 1 < arr.length</code>.</li>
<li><code>i - 1</code> where: <code>i - 1 >= 0</code>.</li>
<li><code>j</code> where: <code>arr[i] == arr[j]</code> and <code>i != j</code>.</li>
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 don't 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.
Example 4:
Input: arr = [6,1,9] Output: 2
Example 5:
Input: arr = [11,22,7,7,7,7,7,7,7,22,13] Output: 3
Constraints:
<li><code>1 <= arr.length <= 5 * 10^4</code></li>
<li><code>-10^8 <= arr[i] <= 10^8</code></li>