I think there is a VERY BIG hole in this question

  • 3

    When I checked some others solutions committed and passed, I found that, they all miss the checking step,which means we need to check if there are both p and q in this tree.

    for example,there is a question name called Share C++/C# 24ms recursive solution , the solution it shows doesn't check wether TreeNode p and TreeNode q exist when it returns.

    So what do you guys think??

  • 2

    If TreeNode p or q can not be found in the tree, then the result should be NULL which means LCA of p and q doesn't exist. But this case doesn't be tested in current test cases, I suppose.

  • 0

    Also the meaning of "lowest" is not validated in the test case.

    for example, for tree [1,1,null,2,3], the LCA for 1, 2 is the root->left.

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