// removeSubsets
// Given an array of nodes, remove any member that is contained by another.
exports.removeSubsets = function(nodes) {
	var idx = nodes.length, node, ancestor, replace;

	// Check if each node (or one of its ancestors) is already contained in the
	// array.
	while (--idx > -1) {
		node = ancestor = nodes[idx];

		// Temporarily remove the node under consideration
		nodes[idx] = null;
		replace = true;

		while (ancestor) {
			if (nodes.indexOf(ancestor) > -1) {
				replace = false;
				nodes.splice(idx, 1);
				break;
			}
			ancestor = ancestor.parent;
		}

		// If the node has been found to be unique, re-insert it.
		if (replace) {
			nodes[idx] = node;
		}
	}

	return nodes;
};