64. 最小路径和

 class Solution {
        public int minPathSum(int[][] grid) {
            int m = grid.length, n = grid[0].length;
            for (int i = 0; i < m; i++) {
                for (int j = 0; j < n; j++) {
                    if (i == 0 && j == 0) {
                        continue;
                    }else if (i==0){
                        grid[i][j]+=grid[i][j-1];
                    }else if (j==0){
                        grid[i][j]+=grid[i-1][j];
                    }else {
                        grid[i][j]+=Math.min(grid[i-1][j],grid[i][j-1]);
                    }
                }
            }
            return grid[m-1][n-1];
        }
    }