lc-741

public int cherryPickup(int[][] grid) {
        int m = grid.length;
        int n = grid[0].length;
        int w = Math.max(m, n);
        int h = m + n -1;
        int INF = -m * n * 2;
        int[][] f = new int[w+1][w+1];
        int[][] g = new int[w+1][w+1];
        for (int i = 0; i <= w; i++) {
            f[0][i] = INF;
            f[i][0] = INF;
            g[0][i] = INF;
            g[i][0] = INF;
        }
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                for (int k = 0; k < w; k++) {
                    int n1 = INF;
                    int n2 = INF;
                    int x1 = i -j;
                    if (x1 >= 0 && x1 < m && j < n && grid[x1][j] != -1) {
                        n1 = grid[x1][j];
                    }
                    int x2 = i - k;
                    if (x2 >= 0 && x2 < m && k < n && grid[x2][k] != -1) {
                        n2 = grid[x2][k];
                    }

                    g[j + 1][k + 1] = max(f[j][k], f[j + 1][k], f[j][k + 1], f[j + 1][k + 1]) + n1 + (j == k ? 0 : n2);
                }
            }
            int[][] t = f;
            f = g;
            g = t;
        }
        return f[w][w] < 0 ? 0 : f[w][w];
    }

    private int max(int ...y) {
        int ans = Integer.MIN_VALUE;
        for (int i : y) {
            ans = Math.max(i, ans);
        }
        return ans;
    }