<p>Given two strings <code>s</code> and <code>t</code>, return <code>true</code> <em>if they are equal when both are typed into empty text editors</em>. <code>'#'</code> means a backspace character.</p> <p>Note that after backspacing an empty text, the text will continue empty.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> s = "ab#c", t = "ad#c" <strong>Output:</strong> true <strong>Explanation:</strong> Both s and t become "ac". </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> s = "ab##", t = "c#d#" <strong>Output:</strong> true <strong>Explanation:</strong> Both s and t become "". </pre> <p><strong>Example 3:</strong></p> <pre> <strong>Input:</strong> s = "a#c", t = "b" <strong>Output:</strong> false <strong>Explanation:</strong> s becomes "c" while t becomes "b". </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code><span>1 <= s.length, t.length <= 200</span></code></li> <li><span><code>s</code> and <code>t</code> only contain lowercase letters and <code>'#'</code> characters.</span></li> </ul> <p> </p> <p><strong>Follow up:</strong> Can you solve it in <code>O(n)</code> time and <code>O(1)</code> space?</p>