Given a binary tree, find the maximum path sum from any two "alive nodes" within the tree. We can assume a node is an alive node if and only if it is a leaf node, indicated by an asterisk below. Example 1 5 / \ 2 0 / / \ *25 *14 *15 Expected answer: 47 = 25 + 2 + 5 + 15 Example 2 5 / \ 2 0 / \ / \ *100 *50 *4 *15 Expected answer: 152 = 100 + 2 + 50 ***/