morse.c

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

// To solve https://www.instagram.com/p/Bt5v_YrlDhz/

const char* alphabet[26] = {
	"2.-",
	"4-...",
	"4-.-.",
	"3-..",
	"1.",
	"4..-.",
	"3--.",
	"4....",
	"2..",
	"4.---",
	"3-.-",
	"4.-..",
	"2--",
	"2-.",
	"3---",
	"4.--.",
	"4--.-",
	"3.-.",
	"3...",
	"1-",
	"3..-",
	"4...-",
	"3.--",
	"4-..-",
	"4-.--",
	"4--.."
};

void lookForWord(const char* input, char output[14], int curChar);

int main() {
	const char* input = "....-.-..-..-";
	char output[14] = "";
	lookForWord(input, output, 0);
	return 0;
}

void lookForWord(const char* input, char output[14], int curChar) {
	if (*input == '\0') {
		output[curChar] = '\0';
		printf("%s\n", output);
		return;
	}
	
	for (char letter = 0; letter < 26; ++letter) {
		if (strstr(input, alphabet[letter]+1) == input) {
			output[curChar] = 'a' + letter;
			lookForWord(input + *alphabet[letter] - '0', output, curChar + 1);
		}
	}
}