Solve 2020 day 23

2020/d23.py

@@ -0,0 +1,73 @@
+from lib import get_data
+
+data = get_data(__file__)
+
+cups = list(map(int, list(data.strip())))
+min_label = min(cups)
+max_label = max(cups)
+
+cmap = {}
+for i in range(len(cups)):
+    cmap[cups[i]] = cups[(i + 1) % len(cups)]
+
+cc = cups[0]
+for _ in range(100):
+    a = cmap[cc]
+    b = cmap[a]
+    c = cmap[b]
+
+    cmap[cc] = cmap[c]
+
+    dest = cc - 1
+    while dest in {a, b, c} or dest < min_label:
+        dest = dest - 1
+        if dest < min_label:
+            dest = max_label
+
+    cmap[c] = cmap[dest]
+    cmap[dest] = a
+
+    cc = cmap[cc]
+
+s = ""
+cup = cmap[1]
+while cup != 1:
+    s += str(cup)
+    cup = cmap[cup]
+print(s)
+
+cups = list(map(int, list(data.strip())))
+current = max(cups) + 1
+while len(cups) != 1_000_000:
+    cups.append(current)
+    current += 1
+
+min_label = min(cups)
+max_label = max(cups)
+cmap = {}
+for i in range(len(cups)):
+    cmap[cups[i]] = cups[(i + 1) % len(cups)]
+
+cc = cups[0]
+for _ in range(10_000_000):
+    a = cmap[cc]
+    b = cmap[a]
+    c = cmap[b]
+
+    cmap[cc] = cmap[c]
+
+    dest = cc - 1
+    while dest in {a, b, c} or dest < min_label:
+        dest = dest - 1
+        if dest < min_label:
+            dest = max_label
+
+    cmap[c] = cmap[dest]
+    cmap[dest] = a
+
+    cc = cmap[cc]
+
+a = cmap[1]
+b = cmap[a]
+
+print(a * b)