Added 2025 day4

2025-12-04 20:30:43 +01:00
parent 97cee5ae24
commit e22496e0ba
2 changed files with 104 additions and 5 deletions
@@ -1,5 +1,5 @@
 #!/bin/python3
-import sys,time,re,os
+import sys,time,re,os,copy
 from pprint import pprint
 sys.path.insert(0, '../../')
 from fred import *
@@ -53,7 +53,104 @@ print('Part 1:',p1, '\t\t', round((time.time() - start_time)*1000), 'ms')
 #########################################

 def part2(): 
-    return 
+    grid = toGrid(input_f)
+
+    directions = ['up','down','left','right','up-left','up-right','down-left','down-right']
+    removed = []
+    score = 0
+    empty = False
+    prev_score = 1 # Set to 1 to avoid exit loop instantly. 
+    tmp = 0
+    while score != prev_score:
+        
+        prev_score = score
+        new_grid = copy.deepcopy(grid) # use deepcopy so the original grid isn't manipulated. Using new_grid=grid will change grid too later on.
+        for ydx,y in enumerate(grid):
+            for xdx, x in enumerate(y):
+                limit = 0
+                if get_value_in_direction(grid,(xdx,ydx)) == '@':
+                    for d in directions:
+                        val = get_value_in_direction(grid,(xdx,ydx),d)
+                        if val == '@':
+                            limit += 1
+                    if limit < 4:
+                        score+=1
+                        new_grid[xdx][ydx] = 'X'
+        grid = copy.deepcopy(new_grid)
+        tmp += 1
+    print(tmp)
+    return score
+
+def get_values_in_dir(grid:list, position:set):
+    values = {}
+    
+    x,y=position
+    
+    
+    offsets = {
+        'up': (-1, 0),
+        'down': (1, 0),
+        'left': (0, -1),
+        'right': (0, 1),
+        'up-left': (-1, -1),
+        'up-right': (-1, 1),
+        'down-left': (1, -1),
+        'down-right': (1, 1)
+    }
+    
+    for key,value in offsets.items():
+        dx, dy = value
+        new_x, new_y = x + dx, y + dy
+
+        if 0 <= new_x < len(grid) and 0 <= new_y < len(grid[new_x]):
+            values[key] = grid[new_x][new_y]
+    return values, grid[x][y]
+
+def part2_optimized(): 
+
+    grid = toGrid(input_f)
+
+    queue = []
+    score = 0
+    
+    offsets = {
+        'up': (-1, 0),
+        'down': (1, 0),
+        'left': (0, -1),
+        'right': (0, 1),
+        'up-left': (-1, -1),
+        'up-right': (-1, 1),
+        'down-left': (1, -1),
+        'down-right': (1, 1)
+    }
+    
+    for ydx,y in enumerate(grid):
+        for xdx, x in enumerate(y):
+            values,center = get_values_in_dir(grid,(xdx,ydx))
+
+            if center == '@' and sum(v == '@' for v in values.values()) < 4:
+                queue.append((xdx,ydx))
+    
+    while len(queue) > 0:
+        (x,y) = queue.pop()
+        grid[x][y] = '.'
+        score += 1
+
+        neighbors,center = get_values_in_dir(grid,(x,y))
+        
+        for key,value in neighbors.items():
+            if value == '@':
+                pos = addTuples((x,y),offsets[key])
+                values,center = get_values_in_dir(grid,pos)
+                if sum(value == '@' for value in values.values()) < 4:
+                    if pos not in queue:
+                        queue.append(pos)                
+    
+    return score
+
+start_time = time.time()
+p2 = part2_optimized()
+print('Part 2:',p2, '', round((time.time() - start_time)*1000), 'ms')

 start_time = time.time()
 p2 = part2()