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

if (grid == null || grid.length == 0) return 0;

for (int i = 1; i < grid[0].length; i++) {

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

}

for (int i = 1; i < grid.length; i++) {

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

}

for (int i = 1; i < grid.length; i++) {

for (int j = 1; j < grid[i].length; j++) {

grid[i][j] += (grid[i-1][j] < grid[i][j-1] ? grid[i-1][j] : grid[i][j-1]);

}

}

return grid[grid.length-1][grid[grid.length-1].length-1];

}

}