Trie Delete

        // Complexity: O(length of key)
        public boolean removeKey(String key) {
            int keyLength = key.length();
            TrieNode node = root;

            for(int i=0; i < keyLength; i++) {
                int value = charValue(key.charAt(i));
                if(null == node.childs[value]) return false;
                node = node.childs[value];
            }

            // If the given key isn't a key
            if(!node.isLeaf) return false;

            // if key node has any other child mark isLeaf == false and return
            if(childCount(node) > 0) {
                node.isLeaf = false;
                return true;
            }

            // Going bottom to top checking is current node has any child.
            // If no child exist current node should be null
            for(int i = keyLength-1; i >= 0; i--) {
                if(childCount(node) > 0) break;
                TrieNode parent = node.parent;
                parent.childs[charValue(key.charAt(i))] = null;
                node = parent;
            }
            return true;
        }