Create lonely-pixel-ii.py

Author: kamyu104

Python/lonely-pixel-ii.py

@@ -0,0 +1,39 @@
+# Time:  O(m * n)
+# Space: O(m * n)
+
+class Solution(object):
+    def findBlackPixel(self, picture, N):
+        """
+        :type picture: List[List[str]]
+        :type N: int
+        :rtype: int
+        """
+        rows, cols = [0] * len(picture),  [0] * len(picture[0])
+        lookup = collections.defaultdict(int)
+        for i in xrange(len(picture)):
+            for j in xrange(len(picture[0])):
+                if picture[i][j] == 'B':
+                    rows[i] += 1
+                    cols[j] += 1
+            lookup[tuple(picture[i])] += 1
+
+        result = 0
+        for i in xrange(len(picture)):
+            if rows[i] == N and lookup[tuple(picture[i])] == N:
+                for j in xrange(len(picture[0])):
+                     result += picture[i][j] == 'B' and cols[j] == N
+        return result
+
+
+class Solution2(object):
+    def findBlackPixel(self, picture, N):
+        """
+        :type picture: List[List[str]]
+        :type N: int
+        :rtype: int
+        """
+        lookup = collections.Counter(map(tuple, picture))
+        cols = [col.count('B') for col in zip(*picture)]
+        return sum(N * zip(row, cols).count(('B', N)) \
+                   for row, cnt in lookup.iteritems() \
+                   if cnt == N == row.count('B'))