lowest common ancestor code example

Example 1: lowest common ancestor in a binary tree

#lca in a binary tree
def lca(root,a,b):
	if root in (None,a,b):
		return root
	left_side=lca(root.left,a,b)
	right_side=lca(root.right,a,b)
	if left_side and right_side:
		return root
	return left_side or right_side

Example 2: C# search a nonbinary tree for common ancestor +nonbinary

public class Node<T> where T:IComparable
{
    public T Value { get; set; }

    public IList<Node<T>> Children { get; set; }

    public override string ToString()
    {
        return Value.ToString();
    }

    public static Func<T, Node<T>, Node<T>> GetFindFirstFunc()
    {
        Func<T, Node<T>,Node<T>> func = null;
        func = (value,currentNode) =>
            {
                if (currentNode.Value.CompareTo(value) == 0)
                {
                    return currentNode;
                }
                if (currentNode.Children != null)
                {
                    foreach (var child in currentNode.Children)
                    {                            
                        var result = func(value, child);
                        if (result != null)
                        {
                            //found the first match, pass that out as the return value as the call stack unwinds
                            return result;
                        }
                    }
                }
                return null;
            };
        return func;
    }

    public static Func<T, Node<T>, IEnumerable<Node<T>>> GetFindAllFunc()
    {
        Func<T, Node<T>, IEnumerable<Node<T>>> func = null;
        List<Node<T>> matches = new List<Node<T>>();
        func = (value, currentNode) =>
        {
            //capture the matches  List<Node<T>> in a closure so that we don't re-create it recursively every time.
            if (currentNode.Value.CompareTo(value) == 0)
            {
                matches.Add(currentNode);
            }
            if (currentNode.Children != null)
            {
                //process all nodes
                foreach (var child in currentNode.Children)
                {
                    func(value, child);
                }
            }
            return matches;
        };
        return func;
    }       
}