- Difficulty: Medium
- Tags: LeetCode, Medium, Stack, Array, Linked List, Monotonic Stack, leetcode-2289, Dynamic Programming, O(n), Hard, DP, Mono Stack
Problem
You are given a 0-indexed integer array nums
. In one step, remove all elements nums[i]
where nums[i - 1] > nums[i]
for all 0 < i < nums.length
.
Return the number of steps performed until nums
becomes a non-decreasing array.
Example 1:
Input: nums = [5,3,4,4,7,3,6,11,8,5,11] Output: 3 Explanation: The following are the steps performed: - Step 1: [5,3,4,4,7,3,6,11,8,5,11] becomes [5,4,4,7,6,11,11] - Step 2: [5,4,4,7,6,11,11] becomes [5,4,7,11,11] - Step 3: [5,4,7,11,11] becomes [5,7,11,11] [5,7,11,11] is a non-decreasing array. Therefore, we return 3.
Example 2:
Input: nums = [4,5,7,7,13] Output: 0 Explanation: nums is already a non-decreasing array. Therefore, we return 0.
Constraints:
1 <= nums.length <= 105
1 <= nums[i] <= 109