Maximum Width Ramp - LeetCode solutions

Problem

A ramp in an integer array nums is a pair (i, j) for which i < j and nums[i] <= nums[j]. The width of such a ramp is j - i.

Given an integer array nums, return **the maximum width of a *ramp* in **nums. If there is no *ramp* in nums, return 0.

Example 1:

Input: nums = [6,0,8,2,1,5]
Output: 4
Explanation: The maximum width ramp is achieved at (i, j) = (1, 5): nums[1] = 0 and nums[5] = 5.

Example 2:

Input: nums = [9,8,1,0,1,9,4,0,4,1]
Output: 7
Explanation: The maximum width ramp is achieved at (i, j) = (2, 9): nums[2] = 1 and nums[9] = 1.

Constraints:

2 <= nums.length <= 5 * 10^4
0 <= nums[i] <= 5 * 10^4

Solution (Java)

class Solution {
    public int maxWidthRamp(int[] nums) {
        int m = nums.length;
        int[] dp = new int[m];
        int minInd = 0;
        int ramp = 0;
        for (int i = 0; i < m; i++) {
            int prInd = minInd;
            while (prInd > 0 && nums[i] >= nums[dp[prInd]]) {
                prInd = dp[prInd];
            }
            dp[i] = prInd;
            if (nums[i] >= nums[prInd]) {
                ramp = Math.max(ramp, i - prInd);
            }
            minInd = nums[i] < nums[minInd] ? i : minInd;
        }
        return ramp;
    }
}

Explain:

nope.

Complexity:

Time complexity : O(n).
Space complexity : O(n).