no message

Author: Chris Wu

problems/stone-game-ii.py

@@ -6,12 +6,17 @@ def helper(start, m):
             if start>=len(piles): return 0
             if start+m*2>=len(piles): return sum(piles[start:])
 
-            stones = float('-inf')
+            max_stones = float('-inf')
             for x in xrange(1, m*2+1):
-                stones = max(stones, sum(piles[start:])-helper(start+x, max(m, x)))
+                max_stones = max(max_stones, sum(piles[start:])-helper(start+x, max(m, x)))
 
-            history[(start, m)] = stones
+            history[(start, m)] = max_stones
             return history[(start, m)]
 
         history = {}
-        return helper(0, 1)
+        return helper(0, 1)
+
+"""
+helper(start, m) := the max stones that the first player will get with given piles[start:] and M.
+max_stones = MAX{ (sum of all the stones) - (max_stones the other player will get) } = MAX{ sum(piles[start:]) - helper(start+x, max(m, x)) }
+"""