Minimum Path Sum

Question

## Problem

Minimum-sum path from top-left to bottom-right of a grid, moving right or down.

## Example
```
[[1,3,1],[1,5,1],[4,2,1]] -> 7
```

## Constraints
- 1 ≤ m,n ≤ 200

## Approach
DP in place; the HackerRank OA is a major filter at Salesforce.