leetcode-100-easy
Same Tree
public boolean isSameTree(TreeNode p, TreeNode q) {
if (p == null && q == null) return true;
if (p != null && q == null) return false;
if (p == null && q != null) return false;
return isSameTree(p.left, q.left) &&
p.val == q.val &&
isSameTree(p.right, q.right);
}