import 2020 aoc

2020/day3/day3.py

@@ -0,0 +1,36 @@
+def check_slope_for_trees(plan, x_right=3, y_down=1):
+    x_max = len(plan[0])
+    y_max = len(plan)
+    
+    x, y = 0, 0
+    tree_count = 0
+    while y < y_max - 1:
+        x += x_right
+        x %= x_max  # wrap x
+        y += y_down
+
+        pos = plan[y][x]
+        if pos == '#':
+            tree_count += 1
+    return tree_count
+
+
+def part1(inp):
+    plan = [line.rstrip() for line in open(inp)]
+    tree_count = check_slope_for_trees(plan)
+    print(f"number of trees : {tree_count}")
+
+
+def part2(inp):
+    plan = [line.rstrip() for line in open(inp)]
+    slopes = [{"x": 1, "y": 1}, {"x": 3, "y": 1}, {"x": 5, "y": 1}, {"x": 7, "y": 1}, {"x": 1, "y": 2}]
+    tree_product = 1
+    for slope in slopes:
+        tree_count = check_slope_for_trees(plan, slope["x"], slope["y"])
+        tree_product *= tree_count
+        print(f"slope {slope} number of trees : {tree_count}")
+        print(f"Cumulative product of tress : {tree_product}")
+
+if __name__ == "__main__":
+    part1('input.txt')
+    part2('input.txt')