Add day 3 solutions

1 files changed, 38 insertions, 0 deletions

diff --git a/2017/03/puzzle-2.awk b/2017/03/puzzle-2.awk
new file mode 100755
index 0000000..0758658
--- /dev/null
+++ b/2017/03/puzzle-2.awk
@@ -0,0 +1,38 @@
+#!/usr/bin/env -S awk -f
+
+function move(xi, yi)
+{
+	for (k = 0; k < j; k++) {
+		if (xi)
+			x += xi
+		else
+			y += yi
+
+		spiral[y][x] = spiral[y][x - 1] + spiral[y][x + 1] + spiral[y + 1][x + 1] \
+				+ spiral[y + 1][x] + spiral[y + 1][x - 1] + spiral[y - 1][x + 1] \
+				+ spiral[y - 1][x] + spiral[y - 1][x - 1]
+		if (spiral[y][x] > n)
+			return spiral[y][x]
+	}
+	return 0
+}
+
+{ n = $1 }
+
+END {
+	spiral[0][0] = 1
+	x = y = 0
+	j = 1
+	for (i = 1; 1; i++) {
+		if (i % 2)
+			if (r = move(j % 2 ? 1 : -1, 0))
+				break
+		else {
+			if (r = move(0, j % 2 ? 1 : -1))
+				break
+			j++
+		}
+	}
+
+	print r
+}