[动态规划] leetcode 1049 Last Stone Weight II

问题：https://leetcode.com/problems/last-stone-weight-ii/

       01背包问题，记录不同容量的背包能否被恰好装满即可。

class Solution {
public:
    int lastStoneWeightII(vector<int>& stones) {
        if (stones.size() == 1)
        {
            return stones.front();
        }
        if (stones.size() == 2)
        {
            return abs(stones.front() - stones.back());
        }
        int sum = accumulate(stones.begin(), stones.end(), 0);
        int total = sum;
        sum = sum / 2;

        vector<bool> dp(vector<bool>(sum + 1, false));
        for (int i = 0; i < stones.size(); i++)
        {
            for (int j = sum; j >= stones[i] + 1; j--)
            {
                dp[j] = dp[j] | dp[j - stones[i]];
            }
            dp[stones[i]] = true;
        }
    
        for (int i = sum; i >= 0; i--)
        {
            if (dp[i])
            {
                return abs((total - i) - i);
            }
        }
        return 0;
    }
};