2 files changed, 50 insertions(+), 1 deletions(-)

M README.md
A cd/cd.py

@@ 1,6 1,6 @@
 # Kattis Solutions
 
-My personal solutions to [Kattis](kattis) problems in various languages.
+My personal solutions to [Kattis][kattis] problems in various languages.
 
 [kattis](https://open.kattis.com)
 

@@ 0,0 1,49 @@
+"""
+CD
+    Jack and Jill have decided to sell some of their Compact Discs, while they 
+    still have some value. They have decided to sell one of each of the CD titles 
+    that they both own. How many CDs can Jack and Jill sell?
+    Neither Jack nor Jill owns more than one copy of each CD.
+
+Input
+    The input consists of a sequence of test cases. The first line of each test 
+    case contains two positive integers N and M, each at most one million, 
+    specifying the number of CDs owned by Jack and 
+    by Jill, respectively. This line is followed by N lines listing the catalog 
+    numbers of the CDs owned by Jack in increasing order, and M more lines listing 
+    the catalog numbers of the CDs owned by Jill in increasing 
+    order. Each catalog number is a positive integer no greater than one 
+    billion. The input is terminated by a line containing two zeros. This last line 
+    is not a test case and should not be processed.
+
+Output
+    For each test case, output a line containing one integer, the number of CDs 
+    that Jack and Jill both own.
+
+Algorithm
+    Until reading "0 0",
+        read the test case indicator
+        read all of Jack's CDs into a set s
+        read all of Jill's CDs out of the set s
+        print the result
+
+"""
+s = set()
+while True:
+    n_m = input()
+    if n_m == "0 0":
+        exit()
+    n_m = n_m.split(' ')
+
+    n = int(n_m[0])
+    m = int(n_m[1])
+
+    for i in range(n):
+        s.add(input())
+
+    print(f"Jack's CDS: {s}")
+    for i in range(m):
+        s.discard(input())
+    print(f"Jill's CDS: {s}")
+
+    print(len(s))