Create 1049.Last-Stone-Weight-II_v2.cpp

Author: wisdompeak

Dynamic_Programming/1049.Last-Stone-Weight-II/1049.Last-Stone-Weight-II_v2.cpp

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+class Solution {
+public:
+    int lastStoneWeightII(vector<int>& stones) 
+    {
+        int sum = accumulate(stones.begin(), stones.end(), 0);
+        vector<int>dp(2*sum+2, false);
+        int offset = sum;
+        
+        dp[stones[0]+offset] = 1;
+        dp[-stones[0]+offset] = 1;
+        
+        for (int i=1; i<stones.size(); i++)
+        {
+            vector<int>dp2(2*sum+2, false);
+            for (int s = -sum; s<= sum; s++)
+            {                
+                if (s-stones[i] >= -sum && s-stones[i] <= sum)
+                    dp2[s+offset] = dp2[s+offset] || dp[s-stones[i]+offset];
+                if (s+stones[i] >= -sum && s+stones[i] <= sum)                
+                    dp2[s+offset] = dp2[s+offset] || dp[s+stones[i]+offset];                
+            }
+            dp = std::move(dp2);
+        }
+                
+        for (int s = 0; s<=sum; s++)
+            if (dp[s+offset])
+                return s;
+        return 0;
+    }
+};