Solve 2021 day 7-11

2021/d10.py

@@ -0,0 +1,63 @@
+from lib import get_data
+
+data = get_data(__file__).strip()
+
+OPEN = "([{<"
+CLOSE = ")]}>"
+
+
+def part1(line):
+    score = {
+        ")": 3,
+        "]": 57,
+        "}": 1197,
+        ">": 25137,
+    }
+    stack = []
+    for c in line:
+        if c in OPEN:
+            stack.append(OPEN.index(c))
+        elif c in CLOSE:
+            ci = CLOSE.index(c)
+            if stack and stack[-1] == ci:
+                stack.pop()
+                continue
+            else:
+                return score[c]
+        else:
+            assert False
+    return 0
+
+
+def part2(line):
+    stack = []
+    for c in line:
+        if c in OPEN:
+            stack.append(OPEN.index(c))
+        elif c in CLOSE:
+            ci = CLOSE.index(c)
+            if stack and stack[-1] == ci:
+                stack.pop()
+                continue
+            else:
+                assert False
+        else:
+            assert False
+    score = 0
+    for v in reversed(stack):
+        score *= 5
+        score += v + 1
+    return score
+
+
+s1 = 0
+s2s = []
+for line in data.splitlines():
+    s = part1(line)
+    if s == 0:
+        s2s.append(part2(line))
+    s1 += s
+
+print(s1)
+s2 = sorted(s2s)[len(s2s) // 2]
+print(s2)