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

/*
 * Given a list of strings, find the list of characters that appear in all strings.
 * Here's an example:
 * input = ['google', 'facebook', 'youtube']
 * output = ['e', 'o']
 */

uint32_t common_characters(const char** strings, const uint32_t* lengths, const uint32_t n, char** output) {
    return 0;
}

int main() {
    const int32_t n = 3;
    const char *(strings[]) = { "google", "facebook", "youtube" };

    uint32_t lengths[n];
    for (int32_t i=0; i<n; ++i) {
        lengths[i] = strlen(strings[i]);
    }

    char* output = NULL;
    uint32_t n_chars = common_characters(strings, lengths, n, &output);

    for (uint32_t i=0; i<n_chars; ++i) {
        printf("%c ", output[i]);
    }
    printf("\n");

    free(output);
    return 0;
}