Steps to Make Array Non-decreasing
<p>You are given a <strong>0-indexed</strong> integer array <code>nums</code>. In one step, <strong>remove</strong> all elements <code>nums[i]</code> where <code>nums[i - 1] &gt; nums[i]</code> for all <code>0 &lt; i &lt; nums.length</code>.</p>

<p>Return <em>the number of steps performed until </em><code>nums</code><em> becomes a <strong>non-decreasing</strong> array</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [5,3,4,4,7,3,6,11,8,5,11]
<strong>Output:</strong> 3
<strong>Explanation:</strong> The following are the steps performed:
- Step 1: [5,<strong><u>3</u></strong>,4,4,7,<u><strong>3</strong></u>,6,11,<u><strong>8</strong></u>,<u><strong>5</strong></u>,11] becomes [5,4,4,7,6,11,11]
- Step 2: [5,<u><strong>4</strong></u>,4,7,<u><strong>6</strong></u>,11,11] becomes [5,4,7,11,11]
- Step 3: [5,<u><strong>4</strong></u>,7,11,11] becomes [5,7,11,11]
[5,7,11,11] is a non-decreasing array. Therefore, we return 3.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [4,5,7,7,13]
<strong>Output:</strong> 0
<strong>Explanation:</strong> nums is already a non-decreasing array. Therefore, we return 0.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li>
</ul>
Stack; Array; Linked List; Monotonic Stack
class Solution {
    public int totalSteps(int[] nums) {
        Deque<Integer> stk = new ArrayDeque<>();
        int ans = 0;
        int n = nums.length;
        int[] dp = new int[n];
        for (int i = n - 1; i >= 0; --i) {
            while (!stk.isEmpty() && nums[i] > nums[stk.peek()]) {
                dp[i] = Math.max(dp[i] + 1, dp[stk.pop()]);
                ans = Math.max(ans, dp[i]);
            }
            stk.push(i);
        }
        return ans;
    }
}