PAT/PATBasic/1050.c

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

int cmp(const void *a, const void *b)
{
	return *(int*)b - *(int*)a;
}

int main()
{
	int N, m, n;
	int array[10000] = {0}, matrix[10000] = {0};

	scanf("%d", &N);
	for (int i = 0; i < N; i++)
		scanf("%d", array + i);

	qsort(array, N, sizeof(int), cmp);

	/* determine m and n */
	for (m = 1; !(m * m >= N && N % m == 0); m++) ;
	n = N / m;

	int x = -1, y = 0, index = 0;
	int horizontal = n, virtical = m;

	while (horizontal > 0 && virtical > 0) {
		for (int i = 0; i < horizontal && virtical > 0; i++)  /* toward right */
			matrix[y * n + ++x] = array[index++];
		virtical--;

		for (int i = 0; i < virtical && horizontal > 0; i++)  /* toward bottom */
			matrix[++y * n + x] = array[index++];
		horizontal--;

		for (int i = 0; i < horizontal && virtical > 0; i++)  /* toward left */
			matrix[y * n + --x] = array[index++];
		virtical--;

		for (int i = 0; i < virtical && horizontal > 0; i++)  /* toward top */
			matrix[--y * n + x] = array[index++];
		horizontal--;
	}

	for (int i = 0; i < m; i++)
		for (int j = 0; j < n; j++)
			printf("%d%c", matrix[i * n + j], j == n - 1 ? '\n' : ' ');

	return 0;
}