02.1, 02.2, 03.1, 03.2

03/03.py

@@ -0,0 +1,39 @@
+
+
+inp = open('input.txt').read().strip().split('\n')
+
+chars = [(i, j, c) for i, line in enumerate(inp) for j, c in enumerate(line) if c!='.' and not '0'<=c<='9']
+
+nums = []
+for i, line in enumerate(inp):
+    line = '.'+line+'.'
+    for j, (l, r) in enumerate(zip(line, line[1:])):
+        if not l.isdigit() and r.isdigit():
+            s = j-1
+        if l.isdigit() and not r.isdigit():
+            nums.append((i, s+1, j-1-s, int(line[s+2:j+1])))
+
+places = {}
+for n, (i, j, l, _) in enumerate(nums):
+    for k in range(j, j+l):
+        places[(i, k)] = n
+        
+sel = set()
+neigh = {(di, dj) for di in range(-1, 2) for dj in range(-1, 2)} - {(0,0)}
+for i, j, _ in chars:
+    for di, dj in neigh:
+        if (i+di, j+dj) in places:
+            sel.add(places[(i+di, j+dj)])
+
+print(sum(nums[i][3] for i in sel))
+
+from math import prod
+s = 0
+for i, j, _ in filter(lambda x: x[2]=='*', chars):
+    sel = set()
+    for di, dj in neigh:
+        if (i+di, j+dj) in places:
+            sel.add(places[(i+di, j+dj)])
+    if len(sel)==2:
+        s += prod(nums[i][3] for i in sel)
+print(s)