From f2301c17e9dbc1a4aeda6821f6e518f5c5e29cc5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gustav=20S=C3=B6rn=C3=A4s?= <gustav@sornas.net>
Date: Tue, 8 Dec 2020 06:21:20 +0100
Subject: day 8

---
 20/py/d08.py | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 20/py/d08.py

diff --git a/20/py/d08.py b/20/py/d08.py
new file mode 100644
index 0000000..c53a6ff
--- /dev/null
+++ b/20/py/d08.py
@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+import sys
+
+
+def pt1(_in):
+    acc = 0
+    loc = 0
+    execed = set()
+    while True:
+        if loc in execed:
+            return acc
+        execed.add(loc)
+        inst, offset = _in[loc][:-1].split() # \n
+        offset = int(offset)
+        if inst == "acc":
+            acc += offset
+            loc += 1
+        elif inst == "jmp":
+            loc += offset
+        else:
+            loc += 1
+
+
+def pt2(_in):
+    def run(prog):
+        acc = 0
+        loc = 0
+        execed = set()
+        while loc < len(prog):
+            if loc in execed:
+                return False, acc
+            execed.add(loc)
+            inst, offset = prog[loc].strip().split()
+            offset = int(offset)
+            if inst == "acc":
+                acc += offset
+                loc += 1
+            elif inst == "jmp":
+                loc += offset
+            else:
+                loc += 1
+        return True, acc
+
+    for i in range(len(_in)):
+        prog = _in.copy()
+        inst, offset = prog[i].strip().split()
+        if inst == "jmp":
+            prog[i] = "nop 0"
+        elif inst == "nop":
+            prog[i] = f"jmp {offset}"
+        else:
+            continue
+        ret, acc = run(prog)
+        if ret:
+            return acc
+
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1:
+        input = open(sys.argv[1], "r").readlines()
+    else:
+        input = open("../input/08", "r").readlines()
+    print(pt1(input))
+    print(pt2(input))
-- 
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