Method maxWidthRamp

MaximumWidthRamp.java:2–22

(int[] nums)

class Solution {
    public int maxWidthRamp(int[] nums) {
        Stack<Integer> stack = new Stack<>(); //N
        int n = nums.length;
        // N
        for(int i=0;i<n;i++){
            if(stack.isEmpty() || nums[stack.peek()] > nums[i]){
                stack.push(i);
            }
        }
        int ans = Integer.MIN_VALUE;
        // N + N-1
        for(int i=n-1;i>=0;i--){
            while(!stack.isEmpty() && nums[stack.peek()] <= nums[i]){
                ans = Math.max(ans, i - stack.pop());
            }
            if(stack.isEmpty()){
                break;
            }
        }
        return ans;
    }
}