Solve 2017/03

2017/03/solve.py

@@ -0,0 +1,64 @@
+import sys
+
+# PART 1
+
+def spiral(nth):
+	length = 1
+	nth -= 1
+	x = 0
+	y = 0
+	while True:
+		x += min(length, nth)
+		nth -= min(length, nth)
+		if nth == 0: return x, y
+		y += min(length, nth)
+		nth -= min(length, nth)
+		if nth == 0: return x, y
+
+		length += 1
+
+		x -= min(length, nth)
+		nth -= min(length, nth)
+		if nth == 0: return x, y
+		y -= min(length, nth)
+		nth -= min(length, nth)
+		if nth == 0: return x, y
+
+		length += 1
+
+def manhattan(x, y):
+	return abs(x) + abs(y)
+
+# PART 2
+
+def store(cap):
+	stored = {(0, 0): 1}
+	nth = 2
+	while True:
+		x, y = spiral(nth)
+		adjacent = 0
+		adjacent += stored.get((x-1, y-1), 0)
+		adjacent += stored.get((x  , y-1), 0)
+		adjacent += stored.get((x+1, y-1), 0)
+		adjacent += stored.get((x-1, y  ), 0)
+		adjacent += stored.get((x+1, y  ), 0)
+		adjacent += stored.get((x-1, y+1), 0)
+		adjacent += stored.get((x  , y+1), 0)
+		adjacent += stored.get((x+1, y+1), 0)
+		stored[(x, y)] = adjacent
+		nth += 1
+
+		if adjacent > cap:
+			return adjacent
+
+def main():
+	nth = 277678
+	print(f"Solutions")
+	x, y = spiral(nth)
+	dist = manhattan(x, y)
+	print(f"Part 1: {dist}")
+	adjacent = store(nth)
+	print(f"Part 2: {adjacent}")
+
+if __name__ == "__main__":
+	main()