Given amxngrid filled with non-negative numbers, find a path from top left to bottom right whichminimizesthe sum of all numbers along its path.
Note:You can only move either down or right at any point in time.
第一种方法m*n 空间复杂度
第二种方法 m空间复杂度
DP formula dp[i+1] = min(dp[i+1], dp[i]) +value[i][j];