<p>T1 and T2 are two very large binary trees. Create an algorithm to determine if T2 is a subtree of T1.</p> <p>A tree T2 is a subtree of T1 if there exists a node n in T1 such that the subtree of n is identical to T2. That is, if you cut off the tree at node n, the two trees would be identical.</p> <p><strong>Note:</strong> This problem is slightly different from the original problem.</p> <p><strong>Example1:</strong></p> <pre> <strong> Input</strong>: t1 = [1, 2, 3], t2 = [2] <strong> Output</strong>: true </pre> <p><strong>Example2:</strong></p> <pre> <strong> Input</strong>: t1 = [1, null, 2, 4], t2 = [3, 2] <strong> Output</strong>: false </pre> <p><strong>Note: </strong></p> <ol> <li>The node numbers of both tree are in [0, 20000].</li> </ol>