Solve 2023:03 "Gear Ratios"

Overslept, took about 55 mins.

2023-python/output/day_03.py

@@ -0,0 +1,68 @@
+from collections import deque
+from output import answer, puzzleinput
+
+n = 3
+title = "Gear Ratios"
+
+
+@answer(1, "Sum of all part numbers is {} in the engine schematic")
+def part_1(presolved):
+    s, _ = presolved
+    return s
+
+
+@answer(2, "Gear ratio sums is {} in the engine schematic")
+def part_2(presolved):
+    _, gr = presolved
+    return gr
+
+
+def presolve(data):
+    adj = (-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1), (1, 0), (1, 1)
+    w = len(data[0])
+    h = len(data)
+    s = list()
+    gr = list()
+    for y in range(w):
+        for x in range(h):
+            if data[y][x] != "." and not data[y][x].isdigit():
+                seen = set()
+                t = list()
+                for oy, ox in adj:
+                    if (y + oy, x + ox) in seen:
+                        continue
+                    if data[y + oy][x + ox].isdigit():
+                        n = deque([data[y + oy][x + ox]])
+                        i = x + ox - 1
+                        while i in range(w) and data[y + oy][i].isdigit():
+                            n.append(data[y + oy][i])
+                            seen.add((y + oy, i))
+                            i -= 1
+                        i = x + ox + 1
+                        while i in range(w) and data[y + oy][i].isdigit():
+                            n.appendleft(data[y + oy][i])
+                            seen.add((y + oy, i))
+                            i += 1
+                        t.append(sum(10**m * int(d) for m, d in enumerate(n)))
+                # part 1
+                s.append(sum(t))
+                # part 2
+                if data[y][x] == "*" and len(t) == 2:
+                    a, b = t
+                    gr.append(a * b)
+
+    return sum(s), sum(gr)
+
+
+@puzzleinput(n)
+def parse_input(data):
+    return data.split()
+
+
+if __name__ == "__main__":
+    parsed = presolve(parse_input())
+    a = part_1(parsed)
+    b = part_2(parsed)
+
+    assert a == 553825
+    assert b == 93994191