状态转移方程： f[i][j]=max(f[i+1][j]*2+f[i][i], f[i][j-1]*2+f[j][j])

状态初始化： f[i][i] = line * 2

代码：

using namespace std;

const int MAX_N = 81;
__int128 max_Num, lastNum, result;
__int128 dp[MAX_N][MAX_N];
int line[MAX_N];

inline void print(__int128 x) {
    if (x < 0) {
        putchar('-');
        x = -x;
    }
    if (x > 9)
        print(x / 10);
    putchar(x % 10 + '0');
}

inline __int128 read(int i) {
    __int128 x = 0, sign = 1;
    string str = to_string(i);
    for (char ch : str) {
        if ('0' > ch || ch > '9') {
            if (ch == '-')
                sign = -1;
        }
        if (ch >= '0' && ch <= '9') {
            x = x * 10 + ch - '0';
        }
    }
    return x * sign;
}

inline __int128 getDpNum(int start, int end) {
    for (int i = 1; i <= end; ++i) {
        dp[i][i] = read(line[i] * 2);
    }
    for (int i = end - 1; i > 0; --i) {
        for (int j = i + 1; j <= end; ++j) {
            if (dp[i][j - 1] > dp[i + 1][j]) {
                max_Num = dp[i][j - 1];
                lastNum = dp[j][j];
            } else {
                max_Num = dp[i + 1][j];
                lastNum = dp[i][i];
            }
            dp[i][j] = max_Num *2+lastNum;
        }
    }
    return dp[1][end];
}

int main() {
    int row, column;
    cin >> row >> column;
    for (int i = 1; i <= row; ++i) {
//        依次输入每行
        for (int j = 1; j <= column; ++j) {
            cin >> line[j];
        }
//        通过dp获取每行的最大值
        result+=getDpNum(1, column);
    }
    print(result);
    cout << endl;
    return 0;
}