(iOS) Find common ancestor of two UIViews

CommonAncester.swift

//Time complexity:O(N), Space complexity: (1)

func findCommonSuper(_ view1:inout UIView, _ view2:inout UIView) -> UIView? {
    //Get the level of the 2 views
    var level1 = findLevel(view1)
    var level2 = findLevel(view2)
    
    /****/
    //Find the 2 views for the same level
    if level1 > level2 {
        var dif = level1-level2
        while dif > 0 {
            view1 = view1.superview!
            dif -= 1
        }
    } else if level1 < level2 {
        var dif = level2-level1
        while dif > 0 {
            view2 = view2.superview!
            dif -= 1
        }
    }
    /****/

    //Iterate upwords until the common ancestor is found
    while view1 != view2  {
        //No ancestor if superview is nil
        if view1.superview == nil || view2.superview == nil {
            return nil
        }
        //Get the superview
        view1 = view1.superview!
        view2 = view2.superview!
    }
    //we must have reached the common superview
    if view1 == view2 {
        return view1
    }
    return nil
}

//Returns how deep in the tree of subviews the view is.
func findLevel(_ view:UIView) -> Int {
    var level = 0
    var view = view
    while view.superview != nil {
        view = view.superview!
        level += 1
    }
    return level
}

CommonWithUIKit.swift

extension UIView {

    func nearestCommonSuperviewWith(other: UIView) -> UIView? {
        //Starting from self view
        var nearestAncestor: UIView? = self

        //Get the superview until the other view is descendant of the view we ended up
        while let testView = nearestAncestor, !other.isDescendant(of: testView) {
            nearestAncestor = testView.superview
        }

        return nearestAncestor
    }
}