2O15 day 3, 4, and 6 part 1

adventofcode/2015/day6/day6.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+import fileinput
+import re
+
+
+def part1(inp):
+    """
+    Part 1: simple brute force solution. Use a 1D array to represent the grid.
+    Use sice operations whenever possible because they are faster than iterating.
+    """
+    grid = [False] * 1000 * 1000
+    for line in inp:
+        x1, y1, x2, y2 = map(int, re.findall(r"(\d+)", line))
+        x1, x2 = min(x1, x2), max(x1, x2)
+        y1, y2 = min(y1, y2), max(y1, y2)
+        for y in range(y1, y2 + 1):
+            start = y * 1000 + x1
+            end = y * 1000 + x2 + 1
+            # assigning to the slice is faster than iterating
+            if line.startswith("turn on"):
+                grid[start:end] = [True] * (end - start)
+            elif line.startswith("turn off"):
+                grid[start:end] = [False] * (end - start)
+            elif line.startswith("toggle"):
+                for i in range(start, end):
+                    grid[i] = not grid[i]
+    return sum(grid)
+
+
+def main(inp):
+    print("Part 1: ", part1(inp))
+
+
+if __name__ == "__main__":
+    lines = [x.rstrip() for x in fileinput.input()]
+    main(lines)