Solve day 9 task 2

2022/09/b.py

@@ -0,0 +1,96 @@
+import os, argparse
+import numpy as np
+
+debug_print = print
+debug_print = lambda x: x
+
+def solve_task(lines):
+    s = Snake(9)
+    s.print()
+    for line in lines:
+        s.do(line)
+        #s.print()
+    print(f"Tail visited {s.tail_visited()} spaces")
+
+class Snake:
+    def __init__(self, length = 1):
+        self.length = length
+        self.pos = np.array([0, 0])
+        if length > 0:
+            self.body = Snake(length-1)
+        self.visited = set()
+        self.visited.add(tuple(self.pos))
+    
+    def tail_visited(self):
+        if self.length == 0:
+            return len(self.visited)
+        else:
+            return self.body.tail_visited()
+
+    def print(self):
+        print(f"{self.length}: {self.pos}")
+        #print(self.visited)
+        if self.length > 0:
+            self.body.print()
+    
+    def do(self, instruction):
+        command = instruction.split(' ')[0]
+        distance = int(instruction.split(' ')[1])
+        for _ in range(distance):
+            self.move(command)
+            self.body.follow(self.pos)
+
+    def move(self, direction):
+        debug_print(f"Moving {direction}")
+        if direction == 'R':
+            self.pos[0] += 1
+        elif direction == 'L':
+            self.pos[0] -= 1
+        elif direction == 'U':
+            self.pos[1] += 1
+        elif direction == 'D':
+            self.pos[1] -= 1
+    
+    def follow(self, new_pos):
+        debug_print(f"Euclidian distance from T:{self.pos} to H:{new_pos} to is {np.linalg.norm(self.pos - new_pos)}")
+        if np.linalg.norm(self.pos - new_pos) >= 2:
+            diff = new_pos - self.pos
+            if diff[0] > 0:
+                self.pos[0] += 1
+            elif diff[0] < 0:
+                self.pos[0] -= 1
+            
+            if diff[1] > 0:
+                self.pos[1] += 1
+            elif diff[1] < 0:
+                self.pos[1] -= 1
+
+            debug_print(f"Tail moving from {self.pos}")
+            self.visited.add(tuple(self.pos))
+            if self.length > 0:
+                self.body.follow(self.pos)
+        else:
+            debug_print(f"Tail not moving from {self.pos}")
+
+
+def read_lines(filename):
+    lines = []
+    with open(filename) as infile:
+        for raw_line in infile:
+            line = raw_line.rstrip()
+            lines.append(line)
+    return lines
+
+def parse_arguments():
+    parser = argparse.ArgumentParser(description="Script that solves the case",epilog="Have a nice day!")
+    parser.add_argument('filename', nargs='?', default="example.txt", help='Input file')
+    args = parser.parse_args()
+    return args
+
+def main():
+    args = parse_arguments()
+    lines = read_lines(args.filename)
+    solve_task(lines)
+
+if __name__ == "__main__":
+    main()

2022/09/example.txt

@@ -1,8 +1,8 @@
-R 4
-U 4
-L 3
-D 1
-R 4
-D 1
-L 5
-R 2
+R 5
+U 8
+L 8
+D 3
+R 17
+D 10
+L 25
+U 20