Reverse String

Given a string S, reverse the string using stack.

Input : "abc"
Return "cba"

Solution:

Time: O(n)
Space: O(n)

public class Solution {
    public String reverseString(String A) {
        Deque<Character> stack = new ArrayDeque<>();
        char[] arr = A.toCharArray();
        for (char c : arr) {
            stack.push(c);
        }
        StringBuilder sb = new StringBuilder();
        while (!stack.isEmpty()) {
            sb.append(stack.pop());
        }
        return sb.toString();
    }
}