import java.util.ArrayDeque;
import java.util.Deque;

public class MonotonicStack {

    public int[] nextGreaterElement(int[] nums) {
        int n = nums.length;
        int[] result = new int[n];
        Deque<Integer> stack = new ArrayDeque<>();

        for (int i = n - 1; i >= 0; i--) {
            while (!stack.isEmpty() && stack.peek() <= nums[i]) {
                stack.pop();
            }
            result[i] = stack.isEmpty() ? -1 : stack.peek();
            stack.push(nums[i]);
        }

        return result;
    }
}