Advent of Code 2024 - Day 6 : Python version

advent_of_code/2024(python)/day6.py

@@ -0,0 +1,88 @@
+
+from day4 import prefix_dir
+
+# def _traverse_matrix_part1(matrix:list[str], x:int, y:int, s:set, dir:str):
+
+#     if matrix[x][y] != 'X':
+#         s.add((x,y))
+
+#     print((x,y))
+#     # check new position
+#     new_x, new_y = x+prefix_dir[dir][0], y+prefix_dir[dir][1]
+#     if new_x<0 or new_x>len(matrix)-1 or new_y<0 or new_y>len(matrix[0])-1:
+#         # have been out of matrix
+#         return
+
+#     new_dir = dir
+#     if matrix[new_x][new_y] == '.':
+#         _traverse_matrix_part1(matrix,new_x,new_y,s,new_dir)
+#         return
+
+#     if matrix[new_x][new_y] == '#':
+#         # meet obstacle, turning 90 degrees
+#         if(dir=="up"):
+#             new_dir = "right"
+#         elif(dir=="right"):
+#             new_dir = "down"
+#         elif(dir=="down"):
+#             new_dir = "left"
+#         else:
+#             new_dir = "up"
+
+#     new_x, new_y = x+prefix_dir[new_dir][0], y+prefix_dir[new_dir][1]
+#     if new_x<0 or new_x>len(matrix)-1 or new_y<0 or new_y>len(matrix[0])-1:
+#         return
+
+#     _traverse_matrix_part1(matrix,new_x,new_y,s,new_dir)
+
+def _traverse_matrix_part1(matrix:list[str], x:int, y:int, s:set, dir:str):
+
+    while True:
+
+        if matrix[x][y] != 'X':
+            s.add((x,y))
+
+        print((x,y))
+    # check new position
+        new_x, new_y = x+prefix_dir[dir][0], y+prefix_dir[dir][1]
+        if new_x<0 or new_x>len(matrix)-1 or new_y<0 or new_y>len(matrix[0])-1:
+            # have been out of matrix
+            break
+
+
+        if matrix[new_x][new_y] == '.' or matrix[new_x][new_y]=='^':
+            x,y = new_x, new_y
+        else:
+            # meet obstacle, turning 90 degrees
+            new_dir = dir
+            if(dir=="up"):
+                new_dir = "right"
+            elif(dir=="right"):
+                new_dir = "down"
+            elif(dir=="down"):
+                new_dir = "left"
+            else:
+                new_dir = "up"
+
+            new_x, new_y = x+prefix_dir[new_dir][0], y+prefix_dir[new_dir][1]
+            if new_x<0 or new_x>len(matrix)-1 or new_y<0 or new_y>len(matrix[0])-1:
+                break
+
+            x,y = new_x, new_y
+            dir = new_dir
+
+def solve_day6_part1(matrix:list[str]) -> int:
+    visited_set = set()
+    start_x, start_y = 0, 0
+
+    # firstly decide where the guard is
+    for i in range(len(matrix)):
+        for j in range(len(matrix[0])):
+            if matrix[i][j] == '^':
+                start_x, start_y = i, j
+
+    # next iterate through the whole matrix until out of matrix
+    _traverse_matrix_part1(matrix,start_x,start_y,visited_set,"up")
+
+    return len(visited_set)
+

advent_of_code/2024(python)/test_day6.py

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+import unittest
+
+from day6 import solve_day6_part1
+
+
+matrix_day6 = [
+"....#.....",
+".........#",
+"..........",
+"..#.......",
+".......#..",
+"..........",
+".#..^.....",
+"........#.",
+"#.........",
+"......#...",
+]
+
+
+
+class TestDay4(unittest.TestCase):
+
+    def test_part1(self):
+        self.assertEqual(solve_day6_part1(matrix_day6), 18)
+
+    # def test_part2(self):
+    #     self.assertEqual(solve_day4_part2(matrix_day4), 9)
+
+if __name__ == "__main__":
+    unittest.main()