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