[LeetCode]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.

public class Solution {
private int f[][];
private int g[][];
public int minPathSum(int[][] grid) {
int m = grid.length;
int n = grid[0].length;
f = new int[m+1][n+1];
g= grid;
return dfs(m,n);
}

private int dfs(int m,int n){
if(m<1||n<1) return 2000000000;
if(m==1&&n==1) return g[0][0];
return Math.min(help(m-1,n),help(m,n-1))+g[m-1][n-1];
}

private int help(int m,int n){
if(f[m]
>0) return f[m]
;
return f[m]
= dfs(m,n);
}
}