class Solution {
    public boolean backspaceCompare(String S, String T) {
        return build(S).equals(build(T));
    }

    private String build(final String str) {
        Stack<Character> stack = new Stack<>();

        for(char c : str.toCharArray()) {
            if(c != '#') {
                stack.push(c);
            }
            else if(!stack.empty()) {
                stack.pop();
            }
        }

        return String.valueOf(stack);
    }
}