// updateMask updates n.mask
updateMask updates n.mask
// updateMask updates n . mask
func updateMask(node *trieNode) {
	for ; node != nil; node = node.parent {
		node.mask ^= node.mask
		node.mask |= uint64(1) << uint64(node.rval-'a')
		for _, c := range node.children {
			node.mask |= c.mask
		}
	}
}
func updateMask ( node * trieNode ) { for ; node != nil ; node = node . parent { node . mask ^= node . mask node . mask |= uint64 ( 1 ) << uint64 ( node . rval - 'a' ) for _ , c := range node . children { node . mask |= c . mask } } }
updateMask updates n.mask
updateMask updates n . mask