Day 5

2020/day5_1.py

@@ -1,4 +1,38 @@
+from math import floor, ceil
+
 input = []
 with open('day5_input.txt', 'r') as f:
     for line in f.readlines():
-			input.append(line.strip())
+        input.append(line.strip())
+
+
+def get_row( r, low=0, high=127 ):
+    if len(r) == 0 or low == high:
+        return high
+    else:
+        if r[0] == 'F':
+            return get_row(r[1:], low, floor((high+low)/2))
+        else:
+            return get_row(r[1:], ceil((high+low)/2), high)
+
+def get_col( c, low=0, high=7 ):
+    if len(c) == 0 or low == high:
+        return high
+    else:
+        if c[0] == 'L':
+            return get_col(c[1:], low, floor((high+low)/2))
+        else:
+            return get_col(c[1:], ceil((high+low)/2), high)
+
+def get_seat( bpass ):
+    row = get_row(bpass[:7])
+    col = get_col(bpass[7:])
+    return (row, col, row*8+col)
+
+
+max_seat = 0
+for bpass in input:
+    seat = get_seat(bpass)
+    if seat[2] > max_seat:
+        max_seat = seat[2]
+print(max_seat)

2020/day5_2.py

@@ -0,0 +1,40 @@
+from math import floor, ceil
+
+input = []
+with open('day5_input.txt', 'r') as f:
+    for line in f.readlines():
+        input.append(line.strip())
+
+
+def get_row( r, low=0, high=127 ):
+    if len(r) == 0 or low == high:
+        return high
+    else:
+        if r[0] == 'F':
+            return get_row(r[1:], low, floor((high+low)/2))
+        else:
+            return get_row(r[1:], ceil((high+low)/2), high)
+
+def get_col( c, low=0, high=7 ):
+    if len(c) == 0 or low == high:
+        return high
+    else:
+        if c[0] == 'L':
+            return get_col(c[1:], low, floor((high+low)/2))
+        else:
+            return get_col(c[1:], ceil((high+low)/2), high)
+
+def get_seat( bpass ):
+    row = get_row(bpass[:7])
+    col = get_col(bpass[7:])
+    return (row, col, row*8+col)
+
+seats = []
+for bpass in input:
+    seats.append(get_seat(bpass))
+seats.sort(key=lambda s: s[2])
+
+for i in range(len(seats)-1):
+    if seats[i][2]+1 != seats[i+1][2]:
+        print(seats[i][2]+1)
+        break