Solution to problem 5 part 1

src/Year_2021/P5.py

@@ -56,11 +56,52 @@
 # Consider only horizontal and vertical lines. At how many points do at least
 # two lines overlap?
 
-with open("files/P5.txt", "r") as f:
+from collections import defaultdict
+from typing import DefaultDict, Tuple
+
+with open("files/P5.txt") as f:
     points = [
         points
         for line in f.read().strip().split("\n")
         for points in line.split(" -> ")
     ]
-p1 = points[::2]
+
-p2 = points[1::2]
+
+point_1 = points[::2]
+x1y1 = [int(val) for p in point_1 for val in p.split(",")]
+x_1 = x1y1[::2]
+y_1 = x1y1[1::2]
+
+point_2 = points[1::2]
+x2y2 = [int(val) for p in point_2 for val in p.split(",")]
+x_2 = x2y2[::2]
+y_2 = x2y2[1::2]
+
+
+def get_range(p1: int, p2: int) -> Tuple[int, int, int]:
+    if p1 > p2:
+        step = -1
+        p2 -= 1
+    else:
+        step = 1
+        p2 += 1
+    return p1, p2, step
+
+
+def part_1() -> 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
+
+    print(sum(1 for key in grid.values() if key > 1))
+
+
+if __name__ == "__main__":
+    part_1()