Update number-of-ways-to-build-sturdy-brick-wall.py

Author: kamyu104

Python/number-of-ways-to-build-sturdy-brick-wall.py

@@ -24,11 +24,7 @@ def backtracking(height, width, bricks, total, mask, lookup, patterns):
 
         patterns, lookup = [], set()
         backtracking(height, width, bricks, 0, 0, lookup, patterns)
-        adj = [[] for _ in xrange(len(patterns))]
-        for i, r1 in enumerate(patterns):
-            for j, r2 in enumerate(patterns):
-                if not (r1 & r2):
-                    adj[i].append(j)
+        adj = [[j for j, r2 in enumerate(patterns) if not (r1 & r2)] for r1 in patterns]
         dp = [[1]*len(patterns), [0]*len(patterns)]
         for i in xrange(height-1):
             for j in xrange(len(patterns)):