1 files changed, 24 insertions, 0 deletions
diff --git a/challenge-199/sgreen/python/ch-1.py b/challenge-199/sgreen/python/ch-1.py
new file mode 100755
index 0000000000..aebf116a45
--- /dev/null
+++ b/challenge-199/sgreen/python/ch-1.py
@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+
+import sys
+
+
+def main(n):
+    # Calculate the frequency of each 'integer'
+    freq = {}
+    for i in n:
+        freq[i] = freq.get(i, 0)+1
+
+    solution = 0
+    for f in freq.values():
+        # If a value appears more than once, calculate the number of
+        #  combinations. This is the sum of 1 + ... + f-1.
+        if f > 1:
+            solution += f * (f-1)//2
+
+    # Display the output
+    print(solution)
+
+
+if __name__ == '__main__':
+    main(sys.argv[1:])