剑指 Offer 47. 礼物的最大价值

public int maxValue(int[][] grid) {
        //动态规划
        int m = grid.length;
        int n = grid[0].length;
        for(int i = 1;i<n;i++){
            grid[0][i] = grid[0][i] + grid[0][i-1];
        }
        for(int i = 1;i<m;i++){
            grid[i][0] = grid[i][0] + grid[i-1][0];
        }
        for(int i = 1;i<m;i++){
            for(int j = 1;j<n;j++){
                grid[i][j] = Math.max(grid[i-1][j],grid[i][j-1]) + grid[i][j];
            }
        }
        return grid[m-1][n-1];
    }