fixed 2023 day 3 part 1

y2023/problem03/__init__.py

@@ -1,18 +1,18 @@
 from typing import *
-from collections import Counter
 
+# from collections import Counter
+import re
 
-def part1(inp: str):
-    part_numbers: Set[int] = set()
-    all_numbers: Counter[int] = Counter()
 
+def part1(inp: str):
     grid = inp.split("\n")
 
     def is_symbol(x, y):
         return grid[y][x] != "." and not grid[y][x].isdigit()
 
     x_range = range(len(grid[0]))
     y_range = range(len(grid))
+    part_numbers: List[int] = []
 
     def print_surrounding(x_start, x_end, y):
         for py in range(y - 1, y + 2):
@@ -25,55 +25,38 @@ def print_surrounding(x_start, x_end, y):
             print()
 
     for y, line in enumerate(grid):
-        at_number = False
-        current_number = ""
-        for x, ch in enumerate(line):
-            if (at_number and not ch.isdigit()) or (
-                ch.isdigit() and x == (len(line) - 1)
-            ):
-                # number is done
-                part_number = int(current_number)
-                all_numbers[part_number] += 1
-
-                x_start = x - len(current_number)
-                x_end = x - 1  # we are already one past the end of the number
-
-                # reset
-                at_number = False
-                current_number = ""
-
-                # check if it touches a symbol
-                touches_symbol = False
-
-                # check above and below, including diagonals
-                for i in range(max(0, x_start - 1), min(len(grid[y]) - 1, x_end + 2)):
-                    if y - 1 in y_range and is_symbol(i, y - 1):
-                        touches_symbol = True
-                    if y + 1 in y_range and is_symbol(i, y + 1):
-                        touches_symbol = True
-
-                # and left and right in this row
-                if x_start - 1 in x_range and is_symbol(x_start - 1, y):
+        for m in re.finditer(r"(\d+)", line):
+            # x_start is index where the number begins, x_end is one past the last digit
+            x_start, x_end = m.span()
+            part_number = int(m.group())
+
+            # check if it touches a symbol
+            touches_symbol = False
+
+            # check above and below, including diagonals
+            # for i in range(max(0, x_start - 1), min(len(grid[y]) - 1, x_end + 1)):
+            for i in range(x_start - 1, x_end + 1):
+                if i not in x_range:
+                    continue
+                if y - 1 in y_range and is_symbol(i, y - 1):
                     touches_symbol = True
-                if x_end + 1 in x_range and is_symbol(x_end + 1, y):
+                if y + 1 in y_range and is_symbol(i, y + 1):
                     touches_symbol = True
 
-                if touches_symbol:
-                    part_numbers.add(part_number)
+            # and left and right in this row
+            if x_start - 1 in x_range and is_symbol(x_start - 1, y):
+                touches_symbol = True
+            if x_end in x_range and is_symbol(x_end, y):
+                touches_symbol = True
+
+            if touches_symbol:
+                part_numbers.append(part_number)
 
-                print(f"{part_number} at ({x_start}, {y}), touches={touches_symbol}")
-                print_surrounding(x_start, x_end, y)
-                print()
-            elif ch.isdigit():
-                at_number = True
-                current_number += ch
-    # numbers might be repeated in the input but not always touching a symbol
-    # the sum should include ALL of them
-    # "There are lots of numbers and symbols you don't really understand, but
-    # apparently any number adjacent to a symbol, even diagonally, is a "part
-    # number" and should be included in your sum."
+            # print(f"{part_number} at ({x_start}, {y}), touches={touches_symbol}")
+            # print_surrounding(x_start, x_end, y)
+            # print()
 
-    return sum(n for n in all_numbers.elements() if n in part_numbers)
+    return sum(part_numbers)
 
 
 def part2(inp: str):

y2023/problem03/test_problem03.py

@@ -13,11 +13,11 @@
 
 
 def test_part1_example():
-    # assert part1(example) == 4361
+    assert part1(example) == 4361
 
     ex2 = """..*.
-    .123
-    ...."""
+.123
+...."""
 
     assert part1(ex2) == 123