[WIP] Solution to problem 5 part 2 in Python

src/Year_2021/P5.py

@@ -59,7 +59,7 @@
 from collections import defaultdict
 from typing import DefaultDict, Tuple
 
-with open("files/P5.txt") as f:
+with open("files/test.txt") as f:
     points = [
         points
         for line in f.read().strip().split("\n")
@@ -103,5 +103,62 @@ def part_1() -> None:
     print(sum(1 for key in grid.values() if key > 1))
 
 
+# --- Part Two ---
+
+# Unfortunately, considering only horizontal and vertical lines doesn't give
+# you the full picture; you need to also consider diagonal lines.
+
+# Because of the limits of the hydrothermal vent mapping system, the lines in
+# your list will only ever be horizontal, vertical, or a diagonal line at
+# exactly 45 degrees. In other words:
+
+#     An entry like 1,1 -> 3,3 covers points 1,1, 2,2, and 3,3.
+#     An entry like 9,7 -> 7,9 covers points 9,7, 8,8, and 7,9.
+
+# Considering all lines from the above example would now produce the following
+# diagram:
+
+# 1.1....11.
+# .111...2..
+# ..2.1.111.
+# ...1.2.2..
+# .112313211
+# ...1.2....
+# ..1...1...
+# .1.....1..
+# 1.......1.
+# 222111....
+
+# You still need to determine the number of points where at least two lines
+# overlap. In the above example, this is still anywhere in the diagram with a 2
+# or larger - now a total of 12 points.
+
+# Consider all of the lines. At how many points do at least two lines overlap?
+
+
+def part_2() -> None:
+    grid: DefaultDict[Tuple[int, int], int] = defaultdict(int)
+    for idx in range(len(points) // 2):
+        if x_1[idx] == x_2[idx]:
+            start, stop, step = get_range(y_1[idx], y_2[idx])
+            for pos in range(start, stop, step):
+                grid[x_1[idx], pos] += 1
+        elif y_1[idx] == y_2[idx]:
+            start, stop, step = get_range(x_1[idx], x_2[idx])
+            for pos in range(start, stop, step):
+                grid[pos, y_1[idx]] += 1
+        elif abs(x_1[idx] - x_2[idx]) == abs(y_1[idx] - y_2[idx]):
+            if x_2[idx] > x_1[idx]:
+                start_x, stop_x, step_x = get_range(x_1[idx], x_2[idx])
+                start_y, stop_y, step_y = get_range(y_1[idx], y_2[idx])
+                pos_x = [pos_x for pos_x in range(start_x, stop_x, step_x)]
+                pos_y = [pos_y for pos_y in range(start_y, stop_y, step_y)]
+                for px, py in zip(pos_x, pos_y):
+                    grid[px, py] += 1
+
+    print(sum(1 for key in grid.values() if key > 1))
+
+
 if __name__ == "__main__":
-    part_1()
+    # part_1()
+    part_2()