add solution week 270 tast 1 in python

1 files changed, 26 insertions, 0 deletions

diff --git a/challenge-270/steven-wilson/python/ch-1.py b/challenge-270/steven-wilson/python/ch-1.py
new file mode 100644
index 0000000000..c258062bfa
--- /dev/null
+++ b/challenge-270/steven-wilson/python/ch-1.py
@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+
+from collections import Counter
+
+
+def special_position(matrix):
+    ''' Given a m x n binary matrix, return the number of special positions in
+    the given binary matrix.
+
+        A position (i, j) is called special if $matrix[i][j] == 1 and all other
+        elements in the row i and column j are 0.
+
+    >>> special_position([[1, 0, 0], [0, 0, 1], [1, 0, 0],])
+    1
+    >>> special_position([ [1, 0, 0], [0, 1, 0], [0, 0, 1], ])
+    3
+    '''
+    possible = [row.index(1) for row in matrix if sum(row) == 1]
+    counter = Counter(possible)
+    return sum(1 for value in counter.values() if value == 1)
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod(verbose=True)