added day 09

09/solve02.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python
+
+
+def get_neighour(heightmap, x, y, deltax, deltay):
+	if x+deltax < 0:
+		return 10
+	if y+deltay < 0:
+		return 10
+	try:
+		return heightmap[y+deltay][x+deltax]
+	except IndexError:
+		return 10
+
+def check_low_point(heightmap, x, y):
+	xy = heightmap[y][x]
+	for n in ((1,0),(-1,0),(0,1),(0,-1)):
+		if get_neighour(heightmap,x, y, n[0], n[1]) <= xy:
+			return False
+	return True
+
+def compute_basin(heightmap, x, y):
+	result = 0
+	seen = [(x,y)]
+	queue = [(x,y)]
+	while len(queue):
+		cur = queue.pop(0)
+		v = get_neighour(heightmap, cur[0], cur[1], 0, 0)
+		if v >= 9:
+			continue
+		result += 1
+		for n in ((1,0),(-1,0),(0,1),(0,-1)):
+			i = (cur[0]+n[0], cur[1]+n[1])
+			if i in seen:
+				continue
+			seen.append(i)
+			queue.append(i)
+	return result
+
+heightmap = []
+
+with open("input01.txt","r") as f:
+	for line in f:
+		heightmap.append([int(x) for x in list(line.strip())])
+
+result = []
+for y in range(len(heightmap)):
+	for x in range(len(heightmap[y])):
+		low_point = check_low_point(heightmap, x,y)
+		if low_point:
+			#print("found basin on %d:%d" % (x,y))
+			result.append(compute_basin(heightmap, x, y))
+
+result.sort(reverse=True)
+print(result[0]*result[1]*result[2])