leetcode---64. Minimum Path Sum

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.

Note: You can only move either down or right at any point in time.

版本一

 public int minPathSum(int[][] grid) {       if(grid == null || grid.length==0 || grid[0].length==0)          return 0;         for(int i=1; i<grid.length; i++) grid[i][0] += grid[i-1][0];          for(int j=1; j<grid[0].length; j++) grid[0][j] += grid[0][j-1];          for (int i=1; i<grid.length; i++) {              for (int j=1; j<grid[0].length; j++) {                  grid[i][j] = Math.min(grid[i][j-1], grid[i-1][j]) + grid[i][j];              }          }          return grid[grid.length-1][grid[0].length-1];      }