add day 12

day12/code.py

@@ -0,0 +1,138 @@
+import sys
+sys.path.append('../aoclib')
+
+from aoclib import Input
+from collections import defaultdict
+
+def find_regions(grid: list[list[str]]):
+    regions = []
+    all_visited = set()
+    for y in range(len(grid)):
+        for x in range(len(grid[0])):
+            if (x, y) in all_visited:
+                continue
+
+            val = grid[y][x]
+            region = set()
+            search(val, (x, y), grid, region)
+
+            regions.append((val, region))
+
+            all_visited.update(region)
+
+    return regions
+
+        
+def search(plot_type: str, plot: tuple[int,int], grid: list[list[str]], region: set):
+    x, y = plot
+    if out_ouf_bounds(plot, grid) or plot in region or not grid[y][x] == plot_type:
+        return
+
+    region.add(plot)
+    search(plot_type, (x+1, y), grid, region)
+    search(plot_type, (x-1, y), grid, region)
+    search(plot_type, (x, y+1), grid, region)
+    search(plot_type, (x, y-1), grid, region)
+
+    return
+
+
+def out_ouf_bounds(plot, grid) -> bool:
+    x, y = plot
+    return x < 0 or x >= len(grid[0]) or y < 0 or y >= len(grid)
+
+def region_area_and_perimeter(plots: set[tuple[int, int]]) -> tuple[int, int]:
+    a = len(plots)
+    p = 0
+    for plot in plots:
+        x, y = plot
+        if (x+1, y) not in plots:
+            p += 1
+        if (x-1, y) not in plots:
+            p += 1
+        if (x, y+1) not in plots:
+            p += 1
+        if (x, y-1) not in plots:
+            p += 1
+    return a, p
+
+
+def region_num_sides(plots: set[tuple[int,int]]) -> int:
+    n = 0 
+    
+    for p in plots:
+        # outer corners
+        x, y = p
+        if (x, y-1) not in plots and (x+1, y) not in plots:
+            n += 1
+        if (x+1, y) not in plots and (x, y+1) not in plots:
+            n += 1
+        if (x, y+1) not in plots and (x-1, y) not in plots:
+            n += 1
+        if (x-1, y) not in plots and (x, y-1) not in plots:
+            n += 1
+
+    for p in plots:
+        # inner corners
+        x, y = p
+        if (x, y-1) in plots and (x+1, y) in plots and (x+1, y-1) not in plots:
+            n += 1
+        if (x+1, y) in plots and (x, y+1) in plots and (x+1, y+1) not in plots:
+            n += 1
+        if (x, y+1) in plots and (x-1, y) in plots and (x-1, y+1) not in plots:
+            n += 1
+        if (x-1, y) in plots and (x, y-1) in plots and (x-1, y-1) not in plots:
+            n += 1
+            
+    return n
+
+def find_sides(c: tuple[int, int], plots: set[tuple[int, int]]):
+    x, y = c
+    hor = set()
+    vert = set()
+
+    _x, _y = x, y
+    while (_x, _y) in plots:
+        low = (x, y-1)
+        high = (x, y+1)
+        vert.add((x,y))
+        while low and high:
+            if low in plots:
+                vert.add(low)
+            else:
+                low = None
+            if high in plots:
+                vert.add(high)
+            else:
+                high = None
+    return vert, hor
+
+def solve1(grid: list[list[str]]):
+    regions = find_regions(grid)
+    total = 0
+    for r in regions:
+        a, p = region_area_and_perimeter(r[1])
+        total += a * p
+    return total
+
+
+def solve2(grid: list[list[str]]):
+    regions = find_regions(grid)
+    total = 0
+    for r in regions:
+        a, _ = region_area_and_perimeter(r[1])
+        n = region_num_sides(r[1])
+        total += a * n
+
+    return total
+
+
+if __name__ == '__main__':
+    #grid = Input('input_test.txt').lines_as_lists()
+    grid = Input('input.txt').lines_as_lists()
+
+    #part 1
+    print('part 1:', solve1(grid)) # 1402544
+
+    #part 2
+    print('part 2:', solve2(grid)) # 862486