Data commit

Task/Set-puzzle/C/set-puzzle.c

@@ -0,0 +1,95 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+char *names[4][3] = {
+	{ "red", "green", "purple" },
+	{ "oval", "squiggle", "diamond" },
+	{ "one", "two", "three" },
+	{ "solid", "open", "striped" }
+};
+
+int set[81][81];
+
+void init_sets(void)
+{
+	int i, j, t, a, b;
+	for (i = 0; i < 81; i++) {
+		for (j = 0; j < 81; j++) {
+			for (t = 27; t; t /= 3) {
+				a = (i / t) % 3;
+				b = (j / t) % 3;
+				set[i][j] += t * (a == b ? a : 3 - a - b);
+			}
+		}
+	}
+}
+
+void deal(int *out, int n)
+{
+	int i, j, t, c[81];
+	for (i = 0; i < 81; i++) c[i] = i;
+	for (i = 0; i < n; i++) {
+		j = i + (rand() % (81 - i));
+		t = c[i], c[i] = out[i] = c[j], c[j] = t;
+	}
+}
+
+int get_sets(int *cards, int n, int sets[][3])
+{
+	int i, j, k, s = 0;
+	for (i = 0; i < n; i++) {
+		for (j = i + 1; j < n; j++) {
+			for (k = j + 1; k < n; k++) {
+				if (set[cards[i]][cards[j]] == cards[k])
+					sets[s][0] = i,
+					sets[s][1] = j,
+					sets[s][2] = k,
+					s++;
+			}
+		}
+	}
+
+	return s;
+}
+
+void show_card(int c)
+{
+	int i, t;
+	for (i = 0, t = 27; t; i++, t /= 3)
+		printf("%9s", names[i][(c/t)%3]);
+	putchar('\n');
+}
+
+void deal_sets(int ncard, int nset)
+{
+	int c[81];
+	int csets[81][3]; // might not be enough for large ncard
+	int i, j, s;
+
+	do deal(c, ncard); while ((s = get_sets(c, ncard, csets)) != nset);
+
+	printf("dealt %d cards\n", ncard);
+	for (i = 0; i < ncard; i++) {
+		printf("%2d:", i);
+		show_card(c[i]);
+	}
+	printf("\nsets:\n");
+
+	for (i = 0; i < s; i++) {
+		for (j = 0; j < 3; j++) {
+			printf("%2d:", csets[i][j]);
+			show_card(c[csets[i][j]]);
+		}
+		putchar('\n');
+	}
+}
+
+int main(void)
+{
+	init_sets();
+	deal_sets(9, 4);
+
+	while (1) deal_sets(12, 6);
+
+	return 0;
+}