8-1

8/onestar.py

@@ -0,0 +1,41 @@
+map = []
+def directionVisible(x, y, tree):
+    treevis = True
+    if type(x) == range: # Horizontal
+        for i in x:
+            if map[y][i] >= tree:
+                treevis = False
+                break
+    elif type(y) == range: # Vertical
+        for i in y:
+            if map[i][x] >= tree:
+                treevis = False
+                break
+    return treevis
+
+with open("input.txt", "r") as f:
+    for line in f.readlines():
+        map.append(list(line.strip()))
+H = len(map)
+W = len(map[0])
+
+print(f"Looking at a forest of {H} by {W}, which has {W*H} trees.")
+print(f"It has {(W-2)*2+2*H} edge trees visible")
+
+visible = 0
+
+for y in range(H):
+    for x in range(W):
+        if x == 0 or y == 0 or x == W-1 or y == H-1:
+            # Edge tree
+            visible += 1
+        else:
+            # Center tree
+            tree = map[y][x]
+            if (
+                directionVisible(x, range(y-1, -1, -1), tree) or # Up
+                directionVisible(x, range(y+1, H), tree) or # Down
+                directionVisible(range(x-1, -1, -1), y, tree) or # Left
+                directionVisible(range(x+1, W), y, tree)): # Right
+                visible += 1
+print(visible)