Leetcode-931 Minimum Falling Path Sum(下降路径最小和)

class Solution
{
    public:
        int minFallingPathSum(vector<vector<int>>& A)
        {
            vector<vector<int>> B = A;
            for(int i = 0;i < A.size();i ++)
            {
                for(int j = 0;j < A[i].size();j ++)
                {
                    B[i][j] = A[j][i];
                }
            }
            
            vector<vector<int>> dp = B;
            for(int i = B.size()-2;i >= 0;i --)
            {
                for(int j = 0;j < B.size();j ++)
                {
                    if(j==0)
                    {
                        dp[j][i] = min(dp[j][i+1],dp[j+1][i+1]) + B[j][i];
                    }
                    else if(j==B.size()-1)
                    {
                        dp[j][i] = min(dp[j][i+1],dp[j-1][i+1]) + B[j][i];
                    }
                    else
                    {
                        dp[j][i] = min(dp[j][i+1],min(dp[j+1][i+1],dp[j-1][i+1])) + B[j][i];
                    }
                }
            }
            
            int result = 393939;
            for(int i = 0;i < dp.size();i ++)
            {
                if(dp[i][0] < result)
                    result = dp[i][0];
            }
            return result;
        }
};