Solve 2022 Day 9 part 1 in python

Author: garritfra

2022/Day9/python/solve.py

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+from collections import defaultdict
+from functools import reduce
+import os
+import re
+
+
+def column(matrix, i):
+    return [row[i] for row in matrix]
+
+
+def part1(lines: list[str]):
+    grid = defaultdict()
+    pos_head = (0, 0)
+    pos_tail = (0, 0)
+
+    grid[pos_head] = True
+    for line in lines:
+        parts = line.split()
+        instruction = (parts[0], int(parts[1]))
+
+        for i in range(instruction[1]):
+            if instruction[0] == "R":
+                pos_head = (pos_head[0] + 1, pos_head[1])
+                delta = [x - y for x, y in zip(pos_head, pos_tail)]
+                if abs(delta[0]) > 1 or abs(delta[1]) > 1:
+                    pos_tail = (pos_tail[0] + 1, pos_tail[1] + delta[1])
+            if instruction[0] == "L":
+                pos_head = (pos_head[0] - 1, pos_head[1])
+                delta = [x - y for x, y in zip(pos_head, pos_tail)]
+                if abs(delta[0]) > 1 or abs(delta[1]) > 1:
+                    pos_tail = (pos_tail[0] - 1, pos_tail[1] + delta[1])
+            if instruction[0] == "U":
+                pos_head = (pos_head[0], pos_head[1] + 1)
+                delta = [x - y for x, y in zip(pos_head, pos_tail)]
+                if abs(delta[0]) > 1 or abs(delta[1]) > 1:
+                    pos_tail = (pos_tail[0] + delta[0], pos_tail[1] + 1)
+            if instruction[0] == "D":
+                pos_head = (pos_head[0], pos_head[1] - 1)
+                delta = [x - y for x, y in zip(pos_head, pos_tail)]
+                if abs(delta[0]) > 1 or abs(delta[1]) > 1:
+                    pos_tail = (pos_tail[0] + delta[0], pos_tail[1] - 1)
+            grid[pos_tail] = True
+            pass
+
+    return len(grid)
+
+
+def part2(lines):
+    pass
+
+
+dirname = os.path.dirname(__file__)
+filename = os.path.join(dirname, '../input.txt')
+with open(filename) as f:
+    lines = f.readlines()
+
+print(part1(lines))
+print(part2(lines))