From 9c619282f40f145dcfa8b7bf20d94871cf0f546a Mon Sep 17 00:00:00 2001
From: Thibaud <thibaud.gasser@gmx.com>
Date: Sun, 6 Dec 2020 15:59:57 +0100
Subject: [PATCH] day 3: another method

---
 day3/day3.py  |  2 +-
 day5/day5.py  | 51 ++++++++++++++++++++++++++++++---------------------
 day5/tests.py |  9 +++++++--
 3 files changed, 38 insertions(+), 24 deletions(-)

diff --git a/day3/day3.py b/day3/day3.py
index 270deb2..c1daf39 100644
--- a/day3/day3.py
+++ b/day3/day3.py
@@ -32,5 +32,5 @@ def part2(inp):
         print(f"Cumulative product of tress : {tree_product}")
 
 if __name__ == "__main__":
-    #part1('./input.txt')
+    part1('input.txt')
     part2('input.txt')
diff --git a/day5/day5.py b/day5/day5.py
index eacc64f..df143ce 100644
--- a/day5/day5.py
+++ b/day5/day5.py
@@ -1,5 +1,6 @@
 #! /usr/bin/env python3
 from itertools import product
+from bisect import bisect
 
 
 def main(filename):
@@ -23,34 +24,42 @@ def part1(results):
 def part2(results):
     seat_ids = sorted(x[2] for x in results.values())
     missing_seat_ids = set(range(max(seat_ids))) - set(seat_ids)
-    print(missing_seat_ids)
+    print("Your seat id : ", max(missing_seat_ids))
 
 
-def parse_boarding_pass(boarding_pass):
-    row = _parse(boarding_pass[:7], "F", "B", 128)
-    col = _parse(boarding_pass[7:], "L", "R", 7)
+def parse_boarding_pass(boarding_pass, strategy="binary"):
+    "Poor man's dispatcher"
+    try: 
+        to_call = globals()[f"parse_boarding_pass_{strategy}"]
+        return to_call(boarding_pass)
+    except KeyError:
+        raise KeyError(f"Bad strategy name {strategy}")
+
+
+def parse_boarding_pass_binary(boarding_pass):
+    "Parse boarding pass using a binary conversion"
+    boarding_pass = boarding_pass.translate(str.maketrans("FLBR", "0011"))
+    row = boarding_pass[:7]
+    col = boarding_pass[7:]
+    return int(row, base=2), int(col, base=2)
+
+
+def parse_boarding_pass_bisect(boarding_pass):
+    "Pass boarding pass using bisection algorithm"
+    row = bisect(boarding_pass[:7], lower_option="F", upper_option="B", max=127)
+    col = bisect(boarding_pass[7:], lower_option="L", upper_option="R", max=7)
     return row, col
 
 
-def _parse(inp, lower_option, upper_option, number):
-    rows = slice(0, number - 1)
+def bisect(inp, lower_option, upper_option, max):
+    min_v, max_v = 0, max
     for l in inp:
+        length = max_v - min_v
         if l == lower_option:
-            rows = lower_half(rows)
-        else:
-            rows = upper_half(rows)
-    return rows.start
-
-
-def lower_half(sl: slice):
-    length = sl.stop - sl.start
-    return slice(sl.start, sl.start + length // 2)
-
-
-def upper_half(sl: slice):
-    length = sl.stop - sl.start
-    return slice(1 + sl.start + length // 2, sl.stop)
-
+            max_v = min_v + length // 2
+        elif l == upper_option:
+            min_v = 1 + min_v + length // 2
+    return min_v
 
 def get_seat_id(row, col):
     return 8 * row + col
diff --git a/day5/tests.py b/day5/tests.py
index 489299c..32ace84 100644
--- a/day5/tests.py
+++ b/day5/tests.py
@@ -1,5 +1,5 @@
 #! /usr/bin/env python3
-from day6 import parse_boarding_pass, get_seat_id
+from day5 import *
 
 def tests():
     inputs = {
@@ -9,8 +9,13 @@ def tests():
         "BBFFBBFRLL": (102, 4, 820)
     }
 
+    test("bisect", inputs)
+    test("binary", inputs)
+
+
+def test(strategy, inputs):
     for boarding_pass, expected in inputs.items():
-        row, col = parse_boarding_pass(boarding_pass)
+        row, col = parse_boarding_pass(boarding_pass, strategy=strategy)
         seat_id =  get_seat_id(row, col)
         assert row == expected[0]
         assert col == expected[1]