1 files changed, 43 insertions, 0 deletions
diff --git a/2021/24/solve.c b/2021/24/solve.c
new file mode 100644
index 0000000..8ab524d
--- /dev/null
+++ b/2021/24/solve.c
@@ -0,0 +1,43 @@
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+static const int xs[] = { 14, 14, 14, 12, 15, -12, -12, 12, -7, 13, -8, -5, -10, -7 };
+static const int ys[] = { 14, 2, 1, 13, 5, 5, 5, 9, 3, 13, 2, 1, 11, 8 };
+static const int zs[] = { 1, 1, 1, 1, 1, 26, 26, 1, 26, 1, 26, 26, 26, 26 };
+
+int main(int argc, char *argv[])
+{
+	srand(time(0));
+	long w = 19599999999999;
+
+	char ws[15];
+	while (1) {
+		sprintf(ws, "%lu", w);
+
+		long x = 0, y = 0, z = 0;
+		for (int i = 0; i < 14; i++) {
+			x = z;
+			x %= 26;
+			z /= zs[i];
+			x += xs[i];
+			x = (x == (ws[i] - '0')) ? 0 : 1;
+			y = 25;
+			y *= x;
+			y += 1;
+			z *= y;
+			y = (ws[i] - '0') + ys[i];
+			y *= x;
+			z += y;
+		}
+		if (z == 0) {
+			printf("Found %ld %ld %ld -> %ld\n", w, x, y, z);
+			break;
+		}
+		if (w % 100000 == 0)
+			printf("%ld %ld\n", w, z);
+		w--;
+	}
+	return 0;
+}