#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>


struct Node {
    struct Node* children[10];
    bool isEnd;
};

struct Node* newNode(void) {
    struct Node *nNode = NULL;
    nNode = (struct Node *) malloc(sizeof(struct Node));
    if (nNode) {
        nNode->isEnd = false;
        for (int i = 0; i < 10; i++) {
            nNode->children[i] = NULL;
        }
    }
    return nNode;
}

int numbers[] = {113, 11354, 77777, 255044};

int main(void) {
    struct Node* root = newNode();
    printf("%p\n", root);

    int n_numbers = sizeof(numbers)/sizeof(int);
    
    for (int i = 0; i < n_numbers; i++) {       // Go through all the phone numbers in the global list
        struct Node* pointer = root;            // Create a pointer that points to whatever part of the trie we're working on
        char number[9];                         // A number has 8 + \0 chars
        snprintf(number, 9, "%i", numbers[i]);  // Convert int to string
        int len_number = strlen(number);
        for (int j = 0; j < len_number - 1; j++) {  // loop over chars in the phone number
            if (j == len_number - 1) {          // if we are at the last iteration
                if (pointer->isEnd == true) {   // Check if we've seen the number before
                    printf("Duplicate Number found at element %i, number %s", i, number);
                    break;
                }
                else {                          // if we're at the last iteration, and isEnd isnt true, its either a new number OR we found a prefix
                    bool continues = false;
                    for (int k = 0; k < 10; k++) {
                        if( pointer->children[k] != NULL) {
                            continues = true;
                        };
                    };
                    if (continues == true) {
                        printf("FOUND PREFIX IN NUMBER\n");
                        printf("%s and %s", number, number);
                        while (pointer->isEnd != true) { // follow the first paths you can find
                            for (int k = 0; k < 10; k++) {
                                if( pointer->children[k] != NULL) {
                                    pointer = pointer->children[k];
                                    printf("%c", k + '0');
                                    break;
                                };
                            };
                        };
                        printf("\n");
                        return 0;
                    };
                };
                pointer->isEnd = true;
            }
            else if (pointer->isEnd == true) {  // if we've already seen a shorter number with this prefix
                printf("Found prefix!");
                for (int k = 0; k < j; k++) {
                    printf("%c", number[k]);
                }
                printf("\n");
            };
            int index = number[j+1] - '0';
            pointer->children[index] = newNode();
            pointer = pointer->children[index];
        };
    };
}