public int maxValue(int[][] grid) {

if(grid.length==0 || grid[0].length==0){

return 0;

}

int n = grid.length , m = grid[0].length;

//

int[][] dp = new int[n][m];

dp[0][0] = grid[0][0];

for(int i=1; i<n; i++){

dp[i][0] = dp[i-1][0] + grid[i][0];

}

for(int j=1; j<m; j++){

dp[0][j] = dp[0][j-1] + grid[0][j];

}

for(int i=1; i<n; i++){

for(int j=1; j<m; j++){

dp[i][j] = Math.max(dp[i-1][j], dp[i][j-1]) + grid[i][j];

}

}

return dp[n-1][m-1];

}

}