Lowest common ancestor
= Lowest common ancestor
{wiki=Lowest_common_ancestor}
The lowest common ancestor (LCA) of two nodes in a tree is defined as the deepest node that is an ancestor of both nodes. In a more formal sense, if you have two nodes \\( p \\) and \\( q \\) in a tree, the LCA is the node \\( x \\) such that: 1. \\( x \\) is an ancestor of both \\( p \\) and \\( q \\).