Algebra em C/C++ [RESOLVIDO]

$ cat codigo.c | indent -kr -i8

$ man indent



"(...)all right-thinking people know that (a) K&R are _right_ and (b) K&R are right." - linux/Documentation/CodingStyle - TORVALDS, Linus. 

 

/* prime_sum.c

 *

 * Enzo Ferber

 * 2015

 */

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>



#define __INLINE__	__inline__ __attribute__((__always_inline__))



int __INLINE__ is_prime(int n)

{

	int i;

	for (i = 2; i < n; i++)

		if (!(n % i)) return 0;

	return 1;

}



int __INLINE__ prior_prime(int prime)

{

	while(!is_prime(--prime)) ;

	return prime;

}





int *new_array(int sum, int max)

{

	int *p = malloc(max * sizeof *p);

	register int i;

	for (i = 0; i < max; i++) 

		p[i] = sum;

	return p;

}



int __INLINE__ compute(int *array, int max)

{

	int sum = 0;

	register int i;

	for (i = 0; i < max; i++)

		sum += array[i];

	return sum;

}



void build_sum_array(int *array, int sum, int max)

{

	int *primes, *primes_aux, pp, i, j;



	pp = *array;

	primes = malloc(sum * sizeof *primes); /* overkill */

	primes_aux = primes; 

	for(j = 0; pp > 1; j++) 

		primes[j] = pp = prior_prime(pp); 



	for(i = 0; i < max; i++) {

		for (j = 0; j <= i; j++) {

			pp = *primes;

			while (array[j] > 1) {

				if (compute(array, max) == sum) return;

				array[j] = *primes++;

			}

			array[j] = pp;

			primes = primes_aux;

		}

		if (i == max - 1 && compute(array, max) > sum) {

			i = -1;

			primes = ++primes_aux; /* leaking... */

		}

	}

}



int main(int argc, char *argv[])

{

	if (argc < 3) return 0;



	int sum = atoi(argv[1]);

	int n = atoi(argv[2]);

	int *array = new_array(sum, n);

	register int i;



	printf("%d as a sum of %d primes: \n", sum, n);

	build_sum_array(array, sum, n);

	if (compute(array, n) != sum) {

		puts("Impossible");

		return 0;

	}



	for (i = 0; i < n; i++)

		printf("%-5d ", array[i]);



	putchar('\n');

	return 0;

}



 

$ cat codigo.c | indent -kr -i8

$ man indent



"(...)all right-thinking people know that (a) K&R are _right_ and (b) K&R are right." - linux/Documentation/CodingStyle - TORVALDS, Linus.