C :: Implementing Trie Data Structure With Dynamic Array

i can't implement trie with dynamic array .the problem is in this line i think :

Code:

childs_size = (node_p -> childs_value_p)[0] + 1; here is my code : Code: #include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct trie_node {
unsigned char *childs_value_p; // pointer to an array of child nodes value
struct trie_node **childs_ptp; // pointer to an array of child nodes pointer
struct trie_node *failure_node_p; // pointer to failure node

[code]...

i could write this code with binary tree instead of dynamic array but need a large amount of memory for about 13000000 strings of length 16 . is there any better solution with lower memory usage to implement trie ?