Minimum Path Sum

Problem

Given a grid of size m x n representing a 2D grid where each cell has a non-negative integer, calculate the minimum sum of a path from the top-left corner to the bottom-right corner. You can only move either down or right at any point in time.

Examples

minPathSum([
    [1, 3, 1],
    [1, 5, 1],
    [4, 2, 1]
])
// returns 7
// Because the path 1→3→1→1→1
// minimizes the energy consumption.