Day 11 part 1 of 2020 done in Python

2020/Day 11/Solution.py

@@ -0,0 +1,80 @@
+input_file = "input.txt"
+
+# -1 is floor
+# 0 is empty seat
+# 1 is occupied seat
+
+# Map represents each cell with [current_state,next_state]
+# Would a dictionary be better ?
+seating_map = []
+
+
+def load_map():
+    with open(input_file) as text_map:
+        line = text_map.readline().strip("\n")
+
+        while line:
+            seating_map.append([])
+            for character in line:
+                # Set every seat to occupied as its the first iteration anyway
+                seating_map[-1].append([1 if character == 'L' else -1, 1])
+
+            line = text_map.readline().strip("\n")
+
+
+def run_adjacent_seats():
+    """
+    Run the cellular automata with the following rules :
+        If empty and adjacent are empty, seat
+        If seated and 4 or more neighbours, become empty
+        If floor, pass
+    """
+    load_map()
+
+    game_stable = False
+    occupied_seats = 0
+    iteration = 0
+
+    while not game_stable:
+
+        for i in range(len(seating_map)):
+            for j in range(len(seating_map[0])):
+                current_cell = seating_map[i][j]
+                if current_cell[0] < 0:
+                    continue
+
+                seated_neighbours = 0
+
+                for cell_position in [(i+di, j+dj) for di in [-1, 0, 1] for dj in [-1, 0, 1]]:
+                    if cell_position != (i, j) and \
+                       0 <= cell_position[0] < len(seating_map) and 0 <= cell_position[1] < len(seating_map[0]):
+
+                        seated_neighbours += 1 if seating_map[cell_position[0]][cell_position[1]][0] > 0 else 0
+
+                if current_cell[0] == 0 and seated_neighbours == 0:
+                    current_cell[1] = 1
+                elif current_cell[0] == 1 and seated_neighbours >= 4:
+                    current_cell[1] = 0
+
+        game_stable = True
+        occupied_seats = 0
+
+        # Should be integrated to the first loop to speed things up
+        for i in range(len(seating_map)):
+            for j in range(len(seating_map[0])):
+                current_cell = seating_map[i][j]
+                if current_cell[0] < 0:
+                    continue
+
+                if game_stable and current_cell[0] != current_cell[1]:
+                    game_stable = False
+
+                current_cell[0] = current_cell[1]
+                occupied_seats += current_cell[0]
+
+        iteration += 1
+
+    print(f"The number of occupied seats when stabilized is {occupied_seats}")
+
+
+run_adjacent_seats()