h3. The first idea is that if you have a string of length h, you can insert it in a trie of height h. We could maintain a list of tries,

h3. trie H[N], where H[i] is a trie with height i so when we insert a string with lengght i, we insert it in H[i].

h3. trie H[N], where H[i] is a trie with height i so when we insert a string with length i, we insert it in H[i].

h3. But what happens when we have, say 2 strings, one of length 3, and one with length 10^20^? We can't declare H[10^20^].