LeetCode in Kotlin
962. Maximum Width Ramp
Medium
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 * 1040 <= nums[i] <= 5 * 104
Solution
class Solution {
fun maxWidthRamp(nums: IntArray): Int {
val m = nums.size
val dp = IntArray(m)
var minInd = 0
var ramp = 0
for (i in 0 until m) {
var prInd = minInd
while (prInd > 0 && nums[i] >= nums[dp[prInd]]) {
prInd = dp[prInd]
}
dp[i] = prInd
if (nums[i] >= nums[prInd]) {
ramp = ramp.coerceAtLeast(i - prInd)
}
minInd = if (nums[i] < nums[minInd]) i else minInd
}
return ramp
}
}