LeetCode-503 Next Greater Element II Solution (with Java)

1. Description:

Notes: 

2. Examples:

3.Solutions:

/**
 * Created by sheepcore on 2019-05-10
 */
class Solution {
    public int[] nextGreaterElements(int[] A) {
        int n = A.length, res[] = new int[n];
        Arrays.fill(res, -1);
        Stack<Integer> stack = new Stack<>();
        //We need to loop twice to iterate circularly
        for (int i = 0; i < n * 2; i++) {
            while (!stack.isEmpty() && A[stack.peek()] < A[i % n])
                res[stack.pop()] = A[i % n];
            stack.push(i % n);
        }
        return res;
    }
}