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 * 104class Solution {
public int maxWidthRamp(int[] nums) {
int n = nums.length;
Stack<Integer> indicesStack = new Stack<>();
// Fill the stack with indices in increasing order of their values
for (int i = 0; i < n; i++) {
if (indicesStack.isEmpty() || nums[indicesStack.peek()] > nums[i]) {
indicesStack.push(i);
}
}
int maxWidth = 0;
// Traverse the array from the end to the start
for (int j = n - 1; j >= 0; j--) {
while (
!indicesStack.isEmpty() && nums[indicesStack.peek()] <= nums[j]
) {
maxWidth = Math.max(maxWidth, j - indicesStack.peek());
// Pop the index since it's already processed
indicesStack.pop();
}
}
return maxWidth;
}
}