feat: day 9 part 1 complete

day9/main.py

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+import time
+
+moves = []
+
+input_file = open("input.txt", "r")
+lines = input_file.readlines()
+
+for line in lines:
+    line = line.strip()
+    moves.append((line[0], int(line.split(" ")[-1])))
+
+head = (0, 0)
+tail = (0, 0)
+visited_positions = {tail}
+
+
+def get_tails_new_pos(head, tail):
+    x_diff = head[0] - tail[0]
+    y_diff = head[1] - tail[1]
+
+    if abs(x_diff) <= 1 and abs(y_diff) <= 1:
+        return tail
+
+    new_x = tail[0]
+    new_y = tail[1]
+
+    if abs(x_diff) > 1 and abs(y_diff) >= 1:
+        new_x = tail[0] + x_diff // 2
+        new_y = tail[1] + y_diff
+    elif abs(y_diff) > 1 and abs(x_diff) >= 1:
+        new_y = tail[1] + y_diff // 2
+        new_x = tail[0] + x_diff
+    elif abs(x_diff) > 1:
+        new_x = tail[0] + x_diff // 2
+    elif abs(y_diff) > 1:
+        new_y = tail[1] + y_diff // 2
+
+    return (new_x, new_y)
+
+
+for move in moves:
+    for _ in range(move[1]):
+        if move[0] == "U":
+            head = (head[0] + 1, head[1])
+        elif move[0] == "D":
+            head = (head[0] - 1, head[1])
+        elif move[0] == "R":
+            head = (head[0], head[1] + 1)
+        elif move[0] == "L":
+            head = (head[0], head[1] - 1)
+
+        tail = get_tails_new_pos(head, tail)
+
+        visited_positions.add(tail)
+
+print("Part 1: " + str(len(visited_positions)))

input.txt

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+R 4
+U 4
+L 3
+D 1
+R 4
+D 1
+L 5
+R 2