Add solution for day3

day3/solution.py

@@ -0,0 +1,110 @@
+#!/usr/bin/python3
+
+# http://adventofcode.com/2017/day/3
+
+import sys
+import math
+import numpy as np
+
+n = int(sys.argv[1])
+
+x = 0
+y = 0
+
+state = "right"
+i = 1
+cur_steps = 1
+
+sidelength = math.ceil(math.sqrt(n))
+if sidelength % 2 == 0:
+	sidelength += 1
+print("sidelength", sidelength)
+
+grid = [x[:] for x in [[0]*sidelength]*sidelength]
+grid[sidelength//2][sidelength//2] = 1
+
+def incr_grid(x,y,val):
+	grid[-y + sidelength//2][x + sidelength//2] += val
+
+def get_grid(x,y):	
+	return grid[-y + sidelength//2][x + sidelength//2]
+
+def print_grid():
+	for line in grid:
+		print("\t".join([str(x) for x in line]))
+
+def valid_pos(x,y):
+	return x + sidelength//2 in range(sidelength) \
+	   and -y + sidelength//2 in range(sidelength)
+
+iters = 0
+
+while i < n:	
+	iters += 1
+	cur_steps = min(cur_steps, n-i)
+	i += cur_steps
+
+	if state == "right":
+		for j in range(cur_steps):
+			x += 1
+			y += 0
+			incr_grid(x,y, get_grid(x-1, y))		# left
+			incr_grid(x,y, get_grid(x-1, y+1))  	# left up
+			incr_grid(x,y, get_grid(x, y+1))  		# up
+			if valid_pos(x+1,y+1):
+				incr_grid(x,y, get_grid(x+1, y+1))  # up right
+
+		state = "up"
+
+	elif state == "up":
+		for j in range(cur_steps):
+			x += 0
+			y += 1
+			incr_grid(x,y, get_grid(x, y-1)) 	# down
+			incr_grid(x,y, get_grid(x-1, y-1))	# left down
+			incr_grid(x,y, get_grid(x-1, y))	# left
+			incr_grid(x,y, get_grid(x-1, y+1))	# left up
+
+		state = "left"
+		cur_steps += 1		
+
+	elif state == "left":
+		for j in range(cur_steps):
+			x -= 1
+			y += 0
+			incr_grid(x,y, get_grid(x+1, y))	# right
+			incr_grid(x,y, get_grid(x, y-1))	# down
+			incr_grid(x,y, get_grid(x+1, y-1))  # right down
+			if valid_pos(x-1,y-1):
+				incr_grid(x,y, get_grid(x-1, y-1))  # left down
+			else:
+				print("invalid", x-1, y-1)
+
+		state = "down"
+
+	else: #down
+		for j in range(cur_steps):
+			x += 0
+			y -= 1
+			incr_grid(x,y, get_grid(x+1, y))	# right
+			incr_grid(x,y, get_grid(x, y+1))	# up
+			incr_grid(x,y, get_grid(x+1, y+1))	# right up
+			if valid_pos(x+1,y-1):
+				incr_grid(x,y, get_grid(x+1, y-1))	# right down
+
+		state = "right"
+
+		cur_steps += 1
+
+
+print("part 1")
+print(abs(x)+abs(y))
+
+print("\npart 2")
+flattened = np.array(grid).flatten() 
+filtered = [x for x in flattened if x > n]
+if len(filtered) > 0:
+	print(min(filtered))
+else:
+	print(flattened)
+	print("No x > %d found" % n)