In a trie, each trie node might have multiple branches. So a data structure is used to point to next nodes in branches. The data structure can be an array, a linked list or a hash map. When the data structure is a hash map, the next character stored in the current node is used as the key to find the node to hold the next character in the branch. Using a hash map is the best of three implementations since its put and get operations take O(1) time.