Solve 2020 day 5

2020/d5.py

@@ -0,0 +1,40 @@
+from lib import get_data
+
+
+def part_1(data):
+    rs = []
+    for line in data.splitlines():
+        rl, ru = 0, 127
+        cl, cu = 0, 7
+        for c in line.strip():
+            rh = (ru - rl) // 2
+            ch = (cu - cl) // 2
+            if c == "B":
+                rl = rl + rh + 1
+            elif c == "F":
+                ru = rl + rh
+            elif c == "R":
+                cl = cl + ch + 1
+            elif c == "L":
+                cu = cl + ch
+            else:
+                assert False
+        assert rl == ru
+        assert cl == cu
+        r_new = rl * 8 + cl
+        rs.append(r_new)
+
+    print(max(rs))
+    rs = sorted(rs)
+    for i in range(len(rs) - 1):
+        if rs[i] + 1 != rs[i + 1]:
+            print(rs[i] + 1)
+
+
+def main():
+    data = get_data(__file__)
+    part_1(data)
+
+
+if __name__ == "__main__":
+    main()